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Volume 20, 1887
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Art. I.—On the Freshwater Infusoria of the Wellington District.

[Read before the Wellington Philosophical Society, 30th November, 1887.]

Plates I., II., III., IV.

The following paper is in continuation of that published in vol. xix. of the “Transactions,” and contains some of the observations made since last year by the Microscopical Section of the Wellington Philosophical Society, Messrs. W. F. Barraud, A. Brandon, C. P. Powles, T. W. Kirk, and the writer.

As before, the work has been strictly confined to “freshwater” types. Most of the animals herein considered as new belong to recognised genera: the exception being Thurophora lucens, which seemed undoubtedly to present sufficiently clear generic differences.

In the “Journal of the Royal Microscopical Society” for February, 1887, Professor A. C. Stokes, of New Jersey, in an account of some new American Infusoria, remarks that it is rare to find in America forms which are also found in European fresh water. The experience of the compilers of the present paper leads to quite the contrary view, as regards the New Zealand animalcules. Probably the ambition of every “systematic “observer in any branch of Zoology or Botany is to discover some new species: and this, laudable as it doubtless is to a proper extent, has unfortunately led to a multiplication of specific distinctions and names, often on the slenderest grounds, which subsequent investigation will have to largely diminish, at some trouble to students. The members of the Wellington Microscopical Section have steadily endeavoured to resist this tendency, believing that much less error and confusion will result by neglecting the frequently most minute differences from European types observable in almost every Infusorian examined. Examples of this may be found in such forms as Rhipidodendron

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huxleyi, Amphileptus anser, Metopus sigmoides, in our former paper, or Monas irregularis, Codosiga botrytis, etc., in the present one. There are certainly minute points of difference in such as these which might tempt some observers to raise them, if not to specific, at l'east to “variety,” rank. But, in truth, there is very often no absolute stability even in the same individuals amongst the Infusoria; and we have thought it best to avoid to the utmost any more cumbering of scientific classification and nomenclature than was absolutely necessary. The couple of dozen animalcules herein set down as new species are considered to be sufficiently deserving of the distinction.

But Professor Stokes's statement as to the New Jersey Infusoria, compared with what has just been said, raises a question as to the reason for the identities observed between the New Zealand and the European forms. It may be remarked that similar identities appear to be noticeable also amongst the freshwater Algæ, as several of our Desmidieæ and Diatomaceæ are found at both sides of the globe, and many others present differences so trifling as to be unimportant. That specific similarity should be so rare as Professor Stokes declares it between two countries in the same hemisphere, as New Jersey and France or England, and so frequent in two so nearly antipodal as England and New Zealand, is not a little curious; and it becomes still more so if, as seems to be the case, the differences in the “higher” zoological and botanical orders and families are in a reverse ratio. The “higher” American fauna and flora approximate to the European much more than the New Zealand fauna and flora do. It is, therefore, not quite clear why the microscopical forms of animal and vegetable life should not follow the same lines. The answer might, possibly, be found in an extension of research, leading to comparisons between countries of about the same latitude and climate. Yet New Jersey, France, and New Zealand, are not, in these respects, very differently situated.

Catalogue of Infusoria.
Class I. Flagellata.
Order. Flagellata-Pantostomata.

Genus Monas.

Monas irregularis, Perty. Wellington, Hutt Valley, Wainui, Karori.

Monas claviculus, sp. nov. Plate I., fig. 1, a, b.

Body elongate, rounded and broad anteriorly, tapering to a point posteriorly, plastic and variable in form, nearly five times longer than broad when extended; surface punctate except at

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New Zealand Infusoria.

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the anterior end, where there is a smooth area. Contractile vesicle single, sub-central. Flagellum single, as long as the extended body. Colour white; motion rather slow.

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Length 1/850 inch = 29 μ, extended.

Hutt Valley, W. M. Maskell.

The posterior tapering, smooth anterior area, and general nail-shaped form distinguish this animalcule.

Genus Oikomonas.

Oikomonas termo, James-Clark. Wellington.

Genus Dendromonas.

Dendromonas producta, I., fig. 2, a, b.

Animalcules rounded posteriorly; anterior border oblique, slightly concave, produced at the angles to a point, which is more or less visible according to the position of the animalcule (fig. 2, b). Zoodendrium slender, translucent, erect, irregularly branched but usually only dichotomous at the tip of the main rachis. Fagella two, uneven in length. Contractile vesicle single, sub-central. Endoplast posterior.

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Average total length of zoodendrium 1/280 inch = 90 μ; main rachis usually longer than the branches. Length of zooids 1/4900 inch = 5.7 μ.

Otaki, W. M. Maskell.

The known species of this genus are all more or less pyri-form, and show nothing of the oblique concave anterior edge with produced angles of this species.

Genus Cephalothamnium.

Cephalothamnium coronatum, sp. nov. Plate I., fig. 3.

Animalcules elongate-ovate, situated in a cluster at the extremity of a long, slender, stiff, translucent pedicle: as many as twenty sometimes in a cluster. Flagella two, unequal in length. Near the bases of the flagella is a ring or coronet of very minute granules, sometimes almost like spines. Contractile vesicle single, sub-central. Endoplast not observed.

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Average length of pedicle,1/350 inch = 70 μ; length of zooids,1/2500 inch = 10 μ.

Hutt Valley, W. M. Maskell

The “coronet “of gemmules clearly distinguishes this species.

Genus Stylobryon.

Stylobryon petiolatum, De Fromentel. Karori; Otaki.

Genus Goniomonas.

Goniomonas elongata, sp. nov. Plate I., fig. 4,a, b, c.

Animalcules free-swimming, elongate, sub-triangular or sub-rectangular according to position, persistent in shape; colour

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white or grey, translucent, with numerous greenish granules. Anterior border obliquely truncate, slightly concave. Flagella two, springing from the projecting angle, sub-equal in length. Contractile vesicle single, somewhat posterior. Motion rather rapid.

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Length 1/1050 inch = 23.8 μ.

Wellington, Hutt Valley, Karori, Otaki, W. M. Maskell.

Wants the dark, band-like spot of G. truncata, Fres., and the position of the contractile vesicle and generally more elongated form distinguish it.

Genus Rhipidodendron.

Rhipidodendron splendidum, Stein. Hutt Valley.

The points noted as differentiating this from R. huxleyi, reported in our paper of 1886, are the number of tubes in the branching zoodendrium (seven to ten), their not being in the same plane, and the protrusion of the animalcules in some cases almost entirely beyond the tube-orifices, just as those delineated in Saville Kent's Plate XVI., fig. 1. Curiously, Kent himself says that in R. splendidum the animalcules have “their flagella only projecting; “and he proceeds to figure, as just stated, the animalcules themselves protruded; so that one is apt to be puzzled by the contradiction. The number of tubes, and their situation in different planes, are taken as sufficient distinctions herein. A further character may be the irregularity of the bifurcations as compared with R. huxleyi.

Order. Choano-Flagellata.

Genus Monosiga.

Monosiga brevipes, Kent. Hutt Valley; on stems of Vorticella.

Genus Codosiga.

Codosiga botrytis, Ehrenb. Wellington.

The only differences that close examination revealed between this and the European species were that the colonies were much less frequent, and the individuals of each less numerous, in the New Zealand form.

Genus Salpingæca.

Salpingæca inquillata, Kent. Plate I., fig. 5.

A species only reported from salt-water in Europe. A figure is given to show how closely the Wellington form approximates to the European. The specimens were, however, collected not far from the sea-shore, though in apparently quite fresh water.

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Length of lorica,1/2500 inch = 10μ.

Wellington, A. Brandon.

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Salpingaca steinii, Kent. (var. ?). Plate I., fig. 6.

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Agrees with Kent's species in everything but size, but was found attached to Myriophyllum and not to aquatic animals. It forms rosette-shaped clusters. Note that Kent's measurements (Vol. I., p. 346)—“length of lorica,1/600 inch”—must be a misprint, or else the figures in his Plate V. are inexact.

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Length of lorica,1/200 inch = 12.5μ.

Hutt Valley, W. F. Barraud.

Order. Flagellata-Eustomata.

Genus Trachelomonas.

Trachelomonas hispida, Perty. Wellington.

The New Zealand form seldom shows any neck.

Trachelomonas teres, sp. nov. Plate I., fig. 7.

Lorica evenly elliptical, quite smooth; colour yellow, or reddish-yellow, with a dark-red border; neck represented by a thin ring, the aperture much wider than is usual in the genus. Animalcule greenish.

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Length of lorica, 1/720 inch = 35μ.

Hutt Valley, W. M. Maskell.

Distinct, but nearest perhaps to T. lagenella.

Trachelomonas cylindrica, Ehrenb. Otaki.

Genus Anisonema.

Anisonema grande, Ehrenb. Wellington.

Anisonema ovatum, sp. nov. Plate I., fig. 8, a, b.

Animalcules usually free swimming; evenly ovate when viewed in any direction; colour, white. Flagella springing from points within the anterior edge, ventrally, close to each other and to the pharynx, which is long, narrow, and distinct; anterior flagellum thinner than the posterior one, and about half as long. Contractile vesicle situated near the bases of the flagella. Motion oscillatory, gliding forward.

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Length of body,1/1250 inch = 20μ; length of posterior flagellum, about 1/600 inch.

Otaki, Wellington, W. M. Maskell.

Distinguished by the evenly ovate form in all positions.

Order. Cilio-Flagellata.

Genus Gymnodinium.

Gymnodinium varians, sp. nov. Plate I., fig. 9,a, b.

Animalcules free-swimming, without a cuirass; slightly variable in form, as shown in the figures; body usually as in (a), with conoidal segments equally tapering, sometimes as in

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(b), with globular segments. Colour green. Transverse and longitudinal furrows, and belt of cilia, normal of the genus. Flagellum long, slender.

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Length,1/1400 inch = 17μ.

Hutt Valley, W. M. Maskell.

Allied to G. pulvisculus, Ehrenb.

Gymnodinium fuscum, Ehrenb. Masterton.

Class II. Clliata.
Order. Holotricha.

Genus Nassula.

Nassula ambigua, Stein., var. tumida, Var. nov. Plate I., fig10.

Animalcules free-swimming, flexible, evenly elliptical, cuticle covered with fine cilia. Colour yellow; the ingested food-particles green or brown. Pharynx very large, tumid, dilated at the middle, slightly inclined, situated near the anterior edge; pharyngeal rods conspicuous. Contractile vesicle single, subcentral, situated somewhat posteriorly.

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Length,1/240 inch = 105μ.

Hutt Valley, W. M. Maskell.

This form is rounder and more regular than the European species, and the pharynx is larger and more tumid in the middle.

Genus Chœnia.

Chœnia crassa, sp. nov. Plate I., fig. 11, a, b.

Animalcules free-swimming. Colour brownish-white; not highly extensile but plastic and flexible; vermiform, tapering slightly anteriorly, more so posteriorly; cuticle finely ciliate. Anterior margin a little dilated and rounded, the oral aperture situated at the apex, followed by a narrow alimentary canal, capable of great distension, as shown in fig. 11, b. Contractile vesicles twelve or more, situated along one side. Adoral cilia somewhat longer than the rest.

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Length variable, from 1/30 inch = 833μ to 1/40 inch = 625μ.

Wellington, Hutt Valley, Wainui, Karori, W. M. Maskell.

The European C. teres has a salt-water habitat, and is more slender and much more elastic than this species. Trachelius striatus, Dujardin, is apparently somewhat similar, but seems to be nearly identical with C. teres.

The distension of the oral aperture and canal, shown in fig. 11, b, was observed on one occasion while the animalcule was engaged in devouring another infusorian, Urocentrum turbo, which is here represented as passing head foremost into the

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New Zealand Infusoria.

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mouth. The process, which is apparently similar in the European species, resembles that of a snake, the canal being distended gradually as the food passes down it. The deglutition of Urocentrum on the occasion observed occupied about ten seconds.

Genus Amphileptus.

Amphileptus irregularis, sp. nov. Plate I., fig. 12.

Animalcules free-swimming, elastic; colour whitish; body elongate, tapering posteriorly to a point and produced anteriorly in a very slender recurved neck about two-thirds as long as the body; margins irregular and rough. Oral aperture situated in a conspicuous depression at the base of the neck-region. Cuticle finely ciliated throughout. Contractile vesicles numerous along one edge; nucleus globular, close to the posterior extremity. Surface granular, with many ingested food-particles.

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Average length, 1/150 inch = 166μ; length of neck-region about 1/400 inch = 62μ.

Wellington, Hutt Valley, Otaki, W. M. Maskell.

This might be put into a group with A. gigas, Clap. and Lachm.; but it is much smaller and rougher, and the neckregion is different.

Amphileptus rotundus, sp. nov. Plate II., fig. 13.

Animalcules free-swimming; colour whitish, tinged with brown; many dark ingested food-particles. Cuticle finely ciliated throughout. Body elliptical, slightly pointed posteriorly, produced anteriorly in a very short, thick, curved neck; surface exhibiting many granules except on the neck-region. Oral aperture situated near to but not exactly at the base of the neck, followed by a simple, tubular pharynx. Contractile vesicles numerous. Endoplast elongate, sub-central.

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Length, exclusive of the neck, 1/250 inch = 100μ; length of neck, 1/950 inch = 27μ.

Lyall Bay, W. F. Barraud.

Near to A. vorax, Ehrenb., but differs in the position of the oral aperture and the form of the nucleus. It is also only half as large. The number of contractile vesicles could not be accurately determined, owing to the quantity of dark food-particles in all the specimens examined.

Amphileptus tracheloides, sp. nov. Plate II., fig. 14, a, b.

Animalcules free-swimming, plastic but persistent in form; colour white, with a great number of large black particles all over the body (food ?); cuticle finely ciliate throughout. Body regularly elliptical under one aspect; pyriform under another, and tapering anteriorly, but not produced into a distinct neck-region. Oral aperture situated near the anterior edge, apparently followed by a conical simple pharynx. Contractile vesicle large,

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single, sub-central. Endoplast not observed. All details are extremely difficult of observation, on account of the immense number of black globular particles apparently filling the body. Motion rapid, rolling on the longer axis.

A kind of temporary encystment is frequently to be observed in this species: the animalcules encyst themselves without apparently any particular object, protective or reproductive. An animalcule will slacken the speed of its progress through the water, the motion becoming slower and slower, but very gradually; as it approaches a state of rest it will become quite spherical and surround itself with an apparently mucous, translucent, globular sheath. After perhaps half or three-quarters of an hour all motion will have ceased, except that of the cilia, which slowly vibrate. After awhile (from a few minutes to an hour) the rolling motion will gradually recommence, become by degrees more and more rapid, and at length reach again the normal speed; the animalcule regains its elliptical form and travels as before until it chooses to repeat the process just described. The object of these proceedings is not clear.

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Length,1/120 inch = 200μ.

Otaki, Hutt Valley, Wellington, W. M. Maskell.

A peculiar species, of large size; approaching in its pyriform aspect somewhat Trachelius ovum; but the black particles prevent any observation of vacuolar reticulations. Trachelius also seems never to present an evenly elliptical form.

Order. Heterotricha.

Genus Stentor.

Stentor attenuatus, sp. nov. Plate II., fig. 15, a, b, c.

Body very highly extensile; colour blueish-green; conspicuously striated; excessively slender when fully extended, the stem often becoming as thin as the pedicle of a Vorticella. Peristome narrow, wine-glass shaped, small, the edge scarcely or not at all recurved; edge irregular or wavy, with a small spiral involution. Parenchyma containing several dark granular masses. Contractile vesicle single, situated below the peristome edge, often exhibiting a short attached canal. Endoplast monili-form. Peristomal cilia long; the body and stem clothed with short fine cilia. Body when free-swimming usually elongate (fig. 15, b), pointed posteriorly, conspicuously striated, exhibiting the spiral involution of the peristome; sometimes globular (fig. 15, c). A commencement of reproduction by fissure was observed on one occasion in the fringe, shown in fig. 15 at d.

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Length of peristome (average), 1/60 inch = 417μ; width, 1/80 inch = 312μ. Length of stem when fully extended reaching sometimes ⅛ inch =3125 μ

Wellington, C. P. Powles.

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The remarkable slenderness and great length of the stem clearly distinguish this species. In some specimens examined the stem became, near its base, almost hair-like, with scarcely any dilation until at the commencement of the peristome. The blueish-green colour, conspicuous striæ, and scarcely-expanded peristome-edge are also distinctive. The fringe above mentioned, denoting approaching division, is a character delineated also in Stentor polymorphus, Müller (Kent, Pl. XXX., fig. 14).

Genus Tintinnidium.

Tintinnidium fluviatile, Stein, var. emarginatum, var. nov. Plate III., fig. 16, a, b, c, d.

Animalcules excreting a cylindrical, gelatinous tube or lorica, attached by its base to aquatic plants, or rarely to stems of Zoothamnium or Epistylis; at times free-swimming. Lorica transparent, but usually covered by a quantity of vegetable or other particles adhering to it. Animalcule white, campanulate, attached to the base of the tube by a slender, highly-retractile pedicle; when fully extended reaching only to the mouth of the tube, or projecting very slightly beyond it. Peristome occupying almost all the width of the tube, the edge not at all, or very slightly, recurved. Peristome-edge on one side entire, bearing a number of long, thick, cirrose cilia; the other side bearing very few, shorter, cirrose cilia, and apparently cleft into three divisions, the middle one bearing no cilia; this median division pulsates regularly up and down as on a hinge. On the anterior portion of the body, below the peristome-edge, are a few short, straight, fine setæ placed at right angles to the margin; possibly, if the tube permitted full examination, these might be seen to extend to the pedicle. Contractile vesicle single, spherical, situated a little below the peristome-edge. Nucleus not observed.

Animalcules may frequently be seen unattached within their tubes, as in fig. 16, a (the right-hand figure); they then escape at pleasure from the tube and become free-swimming, in the form shown in fig. 16, c, when they may easily be mistaken for free Vorticellœ. In the end-view of such a form the adoral cilia are seen to be disposed spirally (fig. 16, d) as in Strombidium, and the motion is rapidly rolling.

Food-particles appear to be taken in at the two small clefts on one side of the peristome-edge, shown in fig. 16, b, and the pulsating middle division seems to act after the manner of a valve.

The structural details above given are not easily observed on account of the covering of foreign particles on the lorica, and the fact that the animalcule scarcely protrudes beyond the orifice of the tube. Sometimes, however, a lorica less thickly coated permits fairly close observation.

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Length of animalcule, including pedicle, 1/250 inch = 100μ.

Saville Kent makes no mention of any divisions on the peristome-edge of T. fluviatile, and his description of that species is by no means full. In T. semiciliatum, Sterki, he mentions both a “cleft “oral region and a “lip- or tongue-like organ.” But he seems doubtful whether Sterki's form is not, really the same as Stein's. The main character of T. semiciliatum, if quite certain, is the pectinate form of the adoral cilia. This is not noticeable in our New Zealand animalcule. On the whole, it seems possible that all the freshwater species of this genus may be identical, and the present is only offered as a “variety,” subject to future revision. No species of Tintinnidium seems to have been reported anywhere else since the publication of Kent's monograph.

Order. Peritricha.

Genus Strombidium.

Strombidium intermedium, sp. nov. Plate III., fig. 17, a, b, c.

Animalcules free- swimming, ovoid, with a short posterior prolongation; colour whitish, with enclosed granules; about one and a half times longer than broad; anterior border rounded, posterior projection tapering nearly to a point. On the anterior portion is a ring of long, fine cilia, which in end-view (fig. 17, b) are seen to be disposed spirally. Contractile vesicle single, close to the posterior projection. Nucleus elongate- oval, placed diagonally below the ring of cilia. No cilia on any part except in the ring. Motion excessively rapid, jerking, and difficult to follow.

An example observed of reproduction by fission is shown in fig. 17, c; the two bodies are at right angles to each other.

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Length, 1/875 inch = 38.5μ.

Otaki, W. M. Maskell.

Intermediate between S. claparedii, Kent, and S. gyrans, Stokes.*

Genus Mesodinium.

Mesodinium phialinum, sp. nov. Plate III., fig. 18, a, b.

Animalcules free-swimming, shaped like a small jar or bottle, divided unequally by a ring, at the base of which are a number of longish, straight, fine cilia, which in end-view (fig. 18, b) are seen to be disposed as rays, not spirally; above the ring the body is prolonged in a sub-conical projection, deeply concave at the top. Contractile vesicle single, spherical, placed posteriorly. Nucleus small, spherical, sub-central. Motion excessively rapid, rotatory, varied by violent leaps and jerkings.

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Length, including projection, 1/1400 inch = 17.8μ.

[Footnote] * “Quart. Journ. Roy. Micros. Soc.,” Feb., 1887, p. 37.

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New Zealand Infusoria.

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Otaki, in company with Strombidium, W. M. Maskell.

This form is more angular and. jar-shaped than M. acarus, Stein. M. recurvum, Kellicott,* has two rings of cilia. M. fimbriatum, Stokes, has cilia with divided ends.

Genus Carchesium.

Carchesium polypinum, Linn. Hutt Valley.

Genus Zoothamnium.

Zoothamnium limpidum, sp. nov. Plate III., fig. 19, a, b.

Animalcules regularly campanulate, similar in shape and size when expanded; surface smooth; colour white; placed on branches of a long, thick, quite smooth retractile pedicle, the whole contracting together (the muscular fibre being continuous, Fig. 19, b); peristome-edge of medium thickness, slightly recurved. Contractile vesicle single, sub-central. Nucleus doubtful. The pedicle is, proportionately, a good deal longer than usual in the genus.

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Length of bodies, about 1/300 inch = 83μ. Pedicle sometimes nearly 1/30 inch long before branching.

Wellington, C. P. Powles.

The general smoothness and clearness of the whole zooden-drium, and the comparatively great length of the pedicle, distinguish this form.

Genus Epistylis.

Epistylis anastatica, Linn. Hutt Valley; parasitic on Daphnia pulex.

Genus Opercularia.

Opercularia nutans, Ehrenb. Wellington.

Genus Thuricola.

Thuricola valvata, Wright. Hutt Valley.

Genus Cothurnia.

Cothurnia parallela, sp. nov. Plate III., fig. 20.

Lorica transparent, sub-cylindrical, never ovate, the margin sometimes everted, sides straight and parallel; pedicle always very short, smooth, and slender. Animalcules not occupying all the width, and projecting when extended nearly half their length; colour white; peristome-edge not recurved. Contractile vesicle single, situated below the peristome; nucleus elongated, sub-central.

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Length of lorica, 1/246 inch = 100μ (including pedicle); length of pedicle,1/6000 inch = 4μ.

[Footnote] * “Proc. Amer. Soc. Micros.,” 1885.

[Footnote] † “Journ. Roy. Micros. Soc.,” Feb., 1887.

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On Conferva, Hutt Valley, W. M. Mashell.

Nearest, perhaps, to C. imberbis, Ehrenb., but the form of the lorica is quite different.

Cothurnia amphorella, sp. nov. Plate III., fig. 21.

Lorica transparent, vase-shaped, ovate posteriorly, tapering regularly to the margin, which is narrow and not everted; pedicle very short and slender. Animalcule whitish, occupying about half the width of the ovate portion of the lorica and all the margin, but not projecting when extended except by the peristome-edge, which is rather thick and slightly recurved. Contractile vesicle single, below the peristome; nucleus elongate, sub-central.

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Length of lorica (including pedicle), 1/380 inch = 66μ; length of pedicle, 1/6300 inch = 3.8μ.

On Conferva, Lyall Bay, W. F. Barraud.

The form of the lorica, and the fact that the animalcules do not project beyond the margin, distinguish this species.

Genus Platycola.

Platycola decumbens, Ehrenb., var. intermedia, var. nov. Plate III., fig. 22.

Lorica dark-brown, smooth, oval, decumbent on aquatic plants, produced anteriorly in a very short bent neck, of which the margin is simple and not at all recurved. Animalcule white, protruding when extended nearly half its length beyond the orifice of the lorica. Peristome-edge and ciliary disc not much wider than the body. Contractile vesicle single; nucleus not sufficiently observed. Very often two animalcules (as in fig. 22) occupy the same lorica.

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Length of lorica about 1/200 inch = 125μ.

Wellington, C. P. Powles.

This variety is rather larger than Ehrenberg's original form, and has a distinct neck, which is much shorter and less recurved than in P. longicollis, already reported (1886).

Order. Hypotricha.

Genus Phascolodon.

Phascolodon elongatus, sp. nov. Plate III., fig. 23.

Animalcules free-swimming, persistent in shape but frequently bending upwards at the anterior end; more or less shovel-shaped, broad in front, tapering posteriorly to a point; colour white; ventral surface concave and ciliated; dorsal surface much inflated over half its area from the posterior end, not ciliated; cuticle distinctly striated. Pharynx sub-central, tubular, with conspicuous rods. Contractile vesicles two, one on

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each side of the pharynx. Nucleus round, placed close to the posterior extremity.

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Length 1/190 inch = 131μ.

Wellington, W. M. Maskell.

Longer and narrower than P. vorticella, Stein, and differing also in the positions of the nucleus and the contractile vesicles.

Genus ægyria.

ægyria astyla, sp. nov. Plate IV., fig. 24.

Animalcules free-swimming, persistent in shape; seeming as if bivalved; colour brownish; ventral surface concave, edge furnished with long cilia; dorsal surface convex, not ciliated. Valves narrow, slightly widened posteriorly. Contractile vesicles two; nucleus not observed. No anal style. No pigment-spot.

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Length, 1/350 inch = 70μ; average width of valve, 1/1400 inch = 17.5μ.

Pahautanui, W. M. Maskell.

Most of the species of this genus inhabit salt water. ægyria fluviatilis, Stein, the only freshwater form reported from Europe, appears to be conspicuously ribbed. The presence of an anterior pigment-spot is noticed in one European species,ægyria oliva, C. and L.

ægyria distyla, sp. nov. Plate IV., fig. 25.

Animalcules free-swimming, as if bi-valved, the valves a good deal broader than in the last species; colour brownish-yellow; ventral surface concave, edge furnished with long cilia. A pigment-spot noticeable at the anterior end. At the posterior extremity two short, sharply triangular styles. Contractile vesicle single, sub-central.

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Length, 1/350 inch = 70μ; average width of valve, 1/700 inch = 35μ.

Hutt Valley, W. F. Barraud.

In general contour this resembles æ. oliva, an European saltwater species, but differs in the double anal styles and the single contractile vesicle.

Genus Thurophora, gen. nov. (Gr. θύρα, a door).

Animalcules free-swimming, encuirassed; oral region partly closed by a vibratile, apparently hinged, membrane.

This genus is placed here in the order Hypotricha, because, although in the only species observed there are some short cilia on the dorsal surface, these differ greatly from the long ventral cilia which alone appear to have any locomotive character. The animalcules are, however, sufficiently anomalous to render it somewhat difficult to know where they should strictly be placed. The hinged membrane differs from the extensile pouch of

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Cyclidium or Pleuronema (Holotrichous) in being never retracted and always vibrating. The absence of a pharyngeal tube, or of a distinct peristome-field, is another character separating the genus from other Hypotricha.

Thurophora lucens, sp. nov. Plate IV., fig. 26, a, b, c, d.

Animalcules free-swimming, encuirassed, sub-elliptical when viewed dorsally or ventrally. Colour white, very translucent; cuirass indurated; cuticular surface distinctly striated; in side view elongate, narrow, truncate anteriorly, more or less pointed posteriorly; in end view from the anterior extremity convex above, deeply concave below, the edges incurved. Oral region occuying about three-fourths of the length, ventrally; elliptical, partly closed by a membranous, vibratile process, free on one side and apparently hinged all along the other. At the anterior extremity the oral region forms a very narrow groove, the sides of which are produced in two very short pointed processes bearing a bunch of short setæ; one of these processes is longer than the other. The membranous valve, or door, is very transparent

and difficult to observe; but in the side and end views it may be seen projecting; it appears to bear on its edge some short cilia.

The body bears cilia throughout; but the dorsal cilia are very short, and seem to have no locomotive action; those of the ventral surface are longer and vibratile. The motion of the animalcules is very rapid, gliding, with occasional leaps.

Contractile vesicle single, central, appearing behind the oral membrane when the animalcule is viewed ventrally. Nucleus elongate, irregular, sub-central, rather nearer to the posterior end.

In several specimens observed a bundle of rather long, very fine cilia or setæ appeared at the posterior extremity, as shown in fig. 26, a. These were only to be made out in certain lights, and were not rendered conspicuous even by treatment with osmic acid, iodine, or other re-agents. As the animalcules exhibiting them presented no features distinctive from the others it was not thought advisable to make two species of them.

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Length, 1/400 inch = 62.5μ; width, 1/630 inch = 43.7μ.

Masterton, Otaki, Kaitoki, W. M. Maskell.

This animalcule, which seems fairly common in the localities named, does not agree with any hitherto described. Its rapid motion and very translucent appearance render it extremely difficult to examine it properly. The membranous appendage, as mentioned above, differs essentially from that of the Holotrichous Cyclidium or Pleuronema.

Genus Kerona.

Kerona polyporum, Ehrenb. On Hydra, Waiwetu.

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New Zealand Infusoria.

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Genus Opisthotricha.

Opisthotricha parallela, Engelm, var. minor, var. nov. Plate IV., fig. 27.

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Agrees with the European species in everything but its size, which is only 1/350 inch = 70μ. This dimension was constant in a great number of specimens examined.

Genus Euplotes.

Euplotes charon, Müller. Karori, Hutt Valley.

Class III. Tentaculifera.
Order. Tentaculifera-Suctoria.

Genus Trichophrya.

Trichophyra epistylidis, C. and L. (?) Hutt Valley.

The specimens examined appeared nearly identical with this species, but the tentacles could not be resolved into clearly separate fascicles, seeming rather to be irregularly scattered over the whole body. The animalcules were all on stems of various Algœ; none were observed parasitic on Epistylis.

Genus Acineta.

Acineta flos, sp. nov. Plate IV., fig. 28.

Lorica cup-shaped, width nearly equal to the length, anterior margin deeply cut and produced in several fine points, which bend over slightly inwards; pedicle very little more than half as long as the lorica, very slender. Animalcule sub-globular, a little dilated at the anterior edge, occupying only the upper portion of the lorica; bearing numerous fine tentacles which protrude between the points of the lorica.

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Length of lorica, exclusive of pedicle and points,1/750 inch = 33.3μ.

Wellington, C. P. Powles.

Allied to A. mystacina, Ehrenb., but very much smaller; also the lorica is wider and rounder in proportion.

Acineta angularis, sp. nov. Plate IV., fig. 29.

Lorica trapezoidal, the sides below tapering sharply and straight down to the pedicle; anterior edges angular, produced into two sharp points, which bend over leaving openings at the sides. Pedicle nearly as long as the lorica, tapering to a fine point at the base, wider above. Animalcule irregular, widest anteriorly, occupying only the upper part of the lorica and bearing two fascicles of capitate tentacles, which protrude through the side openings. Contractile vesicle posteriorly situated.

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Length of lorica, exclusive of pedicle and points, somewhat variable, from 1/350 inch = 71μ, to 1/300 inch = 83μ; width at the lower angles 1/430 inch = 58μ.

Wellington, W. M. Maskell.

Allied to A. mystacina, Ehrenb., but the straight sides and sharp angles are constant and distinctive.

Acineta speciosa.

(A elegans, nobis. “Trans. N.Z. Inst.,” vol. xix., p. 60.)

A change in the name of this species is necessary, as our former one had been already appropriated by Imhoff (” Zool. Anzeig.,” 1883) to an animalcule found in some of the Swiss lakes.

Acineta tulipa, sp. nov. Plate IV., fig. 30.

Lorica deep and narrow, not unlike a tulip-flower, the margin five-lobed, distinctly thickened but not recurved; breadth at the top nearly three-fourths the length; sides tapering rapidly and nearly straight to the posterior end, which is rounded. Pedicle very thick, rather short, nearly half the length of the lorica. Animalcule almost filling the lorica; anterior margin very convex. Tentacles arranged in two antero-lateral bundles, each containing nine. Parenchyma irregularly granular. Contractile vesicle spherical, situated near the anterior margin of the lorica, under one of its clefts.

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Length of lorica, 1/350 inch = 71μ; length of pedicle, 1/700 inch = 35μ.

Wanganui, T. W. Kirk.

A distinct and rather elegant species.

Acineta lasanicola, sp. nov. Plate IV., fig. 31.

Lorica shallow, broad, sub-rectangular, having very much the shape of a stewpan; breadth nearly twice the depth; margin neither thickened nor recurved; sides almost parallel, lower angles very obtusely rounded; base slightly concave. Pedicle rather thick, more than twice as long as the depth of the lorica. Animalcule filling the margin of the lorica, but somewhat contracted below, so that it occupies only about three-fourths of the interior space; upper margin convex. Tentacles conspicuously capitate, arranged in two antero-lateral bundles, each containing eleven. Contractile vesicle spherical, sub-central. Endoplast band-like, posterior. Parenchyma granular.

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Depth of lorica,1/460 inch = 54μ; breadth, 1/280 inch = 89μ; length of pedicle, 1/220 inch = 113μ.

Wellington, T. W. Kirk.

A peculiar species, easily distinguished by the saucepan form of the lorica.

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Explanation of Plates I.—IV.
Plate I.
Fig. 1. Monas claviculus × 700; a, extended; b, contracted form.
Fig. 2. Dendromonas producta; a, complete zoodendrium × 700; b, three animalcules and pedicles × 1000.
Fig. 3. Cephalothamnium coronatum × 700.
Fig. 4. Goniomonas elongata × 700, in various positions.
Fig. 5. Salpingæca inquillata, × 1000.
Fig. 6. Salpingæca steinii, var. (?) × 1000.
Fig. 7. Trachelomonas teres, × 600.
Fig. 8. Anisonema ovatum, × 800.
Fig. 9. Gymnodinium varians, × 700.
Fig. 10. Nassula ambigua, var. tumida, × 300.
Fig. 11. Chœnia crassa; a, extended animalcule × 100; b, oral aperture and canal, during inglutition of Urocentrum turbo, × 400.
Fig. 12. Amphileptus irregularis, × 350.
Plate II.
Fig. 13. Amphileptus rotundus, × 350.
Fig. 14. Amphileptus tracheloides, × 200, in different positions.
Fig. 15. Stentor attenuatus × 60; a, extended animalcules; b, c, free-swimming forms; at d, vibratile fringe denoting commencement of propagation by fission.
Plate III.
Fig. 16. Tintinnidium fluviatile, var. emarginatum; a, animalcules in tubes × 350; b, animalcule × 700; c, free-swimming form × 350; d, end-view, free-swimming, × 700.
Fig. 17. Strombidium intermedium, × 700; a, normal animalcule; b, end-view of the same; c, propagation by fission, the new zooid at right angles to the old.
Fig. 18. Mesodinium phialinum, × 700; a, side-view; b, end-view.
Fig. 19. Zoothamnium limpidum; a, zoodendrium × 200; b, portion of stem and branches, showing the continuous muscular fibre, × 700.
Fig. 20. Cothurnia parallela, × 200.
Fig. 21. Cothurnia amphorella, × 350.
Fig. 22. Platycola decumbens, var. intermedia, × 200.
Fig. 23. Phascolodon elongatus, × 350.
Plate IV.
Fig. 24. ægyria astyla, × 350.
Fig. 25. ægyria distyla, × 350.
Fig. 26. Thurophora lucens; a, animalcule, ventral aspect, × 350; b, oral region and membranous valve, × 700; c, side-view of animalcule, × 350; d, section, in end-view, × 350.
Fig. 27. Opisthotricha parallela, var. minor, × 350, dorsal aspect.
Fig. 28. Acineta flos, × 700.
Fig. 29. Acineta angularis, × 350.
Fig. 30. Acineta tulipa, × 350.
Fig. 31. Acineta lasanicola, × 350.