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Volume 41, 1908
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Art. XXXV.—On Two Anemones found in the Neighbourhood of Wellington—Leiotealia thompsoni and Sagartia albocincta.

By F. G. A. Stuckey, M.A.

[Read before the Wellington Philosophical Society, 2nd September, 1908.]

Leiotealia thompsoni.

This anemone was first described by Professor Coughtrey* under the name Actinia thompsoni. Professor Hutton† threw doubts on the correctness of the classification, and Mr. H. Farquhar‡ suggested that it would form the type of a new family of the Artheadæ. The strong endodermal character of the sphincter muscle, however, taken, with the smooth body-wall and numerous perfect mesenteries, determine its place in the genus Leiotealia. This genus, which belongs to the family Bunodidæ, was erected by Richard Hertwig, 1882, for the reception of what were practically smooth-walled Tealidæ. This is referred to more fully in my account of Bunodes aureoradiata. McMurrich's family Cribrinidæ, there mentioned, would contain the genus Leiotealia. Torrey§ considers that Leiotealia is equivalent to Epiactis (Verrill), and gives the older name priority. I have, however, retained Hertwig's name. With the definition of Bunodidæ given in the note referred to above I define Leiotealia as follows: “Bunodidæ without verrucæ or acrorhagi, usually with the mesoglœal folds of the sphincter arranged pinnately, and often with longitudinal furrows in the outer surface of the wall.”

L. thompsoni is one of the finest anemones found near Wellington, its stout tentacles and bright colours making it a very beautiful object when fully expanded.

Pedal-disc.—Adhesive to rocks and boulders. I have found one specimen adhering to an ascidian which was itself fixed to a piece of seaweed. When the animal is detached, the pedal-disc is often dilated to a great extent. Its substance is thin, plainly showing the insertions of the mesenteries. It is rather wider than the column. It presents all the general characteristics of the body-wall, processes of the mesoglœa running outward in the manner to be presently described.

Column.—Cylindrical in shape. Its height can be varied in a rather marked manner in proportion to the diameter of the oral disc. The colour is white and red in alternate longitudinal lines, which, however, are not generally entire, as stated in Professor Coughtrey's description. The colours are deposited in patches, the red in small irregular spots, the white marks being more or less elliptical. This gives the surface of the column a somewhat chequered appearance under a lens of low power. The white markings appear to correspond to the endocœles, the red to the exocœles of the mesenteries. There is a distinct ridge or collar round the top of the column. The colour of preserved specimens completely disappears, when the wall is

[Footnote] * Trans. N.Z. Inst, vol. vii, 1874.

[Footnote] † Trans. N.Z. Inst., vol. xi, 1878.

[Footnote] ‡ Lon. Soc. Journ. Zool., vol. xxvi, p. 528.

[Footnote] § Proc. Wash. Ac. Soc., vol. iv, 1902, pp. 391–92.

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seen to be thrown into parallel ridges which lie close together, running round the body of the animal like hoops round a cask. Each of these folds is wrinkled or pleated, the pleats being so close together and so nearly in line as to almost present the appearance of longitudinal ridges. The result is that both in cross-section and in longitudinal section the wall presents the appearance of being covered with numerous papillæ, into which the mesoglœa runs, often branching or folding in them (Plate XIX, fig. 1). Occasionally the folds grow together and fuse, so that here and there we have in the mesoglœa pits lined with ectoderm (Plate XIX, fig. 2). In cross-sections these appears as more or less circular spaces. The ectoderm peels off in the manner described by McMurrich in his account of Leiotealia badia. It presents the usual histological features. Nuclei are numerous, and crowded towards the outer part, while below this the outlines of the cells form a network. The fibrils of the nervous layer form a more or less continuous line. Nematocysts are present in great quantities, and there is great development of large gland-cells, some of which are lenticular, others pyramidal in shape. The mesoglœa presents a wavy appearance, and has a few large scattered cells. Fine processes of the mesoglœa project inwards, carrying the circular muscle of the wall. This muscle is not continuous all round the body, but is in bands, which overlap each other. The actual endoderm of the body-wall is thin, and does not present any unusual features.

Tentacles.—These are arranged in three cycles—10 in the first or inner, 20 in the second, 30 in the third. This arrangement gives the appearance of their being placed in groups of six, thus: Each tentacle is conical in shape, and very stout. All the tentacles are equal in size. In colour they are of a dull white, with a mauve tip. In a few specimens, which, it is worth noting, were all obtained from Island Bay, the mauve tip was wanting, and in these cases the longitudinal markings of the body-wall appear to be entire. One specimen had light-brown tentacles. There is a pore at the tip of each tentacle. The tentacles of the first two cycles communicate with the endocœles, those of the third cycle with the exocœles of the mesenteries. There is a strong longitudinal muscle borne on numerous fine branching processes of the mesoglœa (Plate XIX, fig. 3). Outside this is the nervous layer in the form of a distinct reticulum. The endodermal or circular muscle of the tentacle is not particularly strong.

Sphincter Muscle (Plate XVIII, fig. 2).—This is very strong, and endodermal in character. It projects into the cœlenterm, and forms a rounded cord, easily seen by the naked eye in a dissection. With a good light behind an expanded specimen the sphincter can be seen through the body-wall. A transverse section of the sphincter presents the same pinnate appearance as that described by McMurrich in the sphincter of L. badia. The endoderm surrounding it is thin. The muscular fibrillæ are seen in cross-section as small swellings on the sides of the branching mesoglœal processes. In a longitudinal section of the sphincter we see the fibres of the mesoglœa running in wavy parallel lines, while beside them are the muscular fibres with their nuclei cut at various angles.

Oral Disc.—The colour is reddish-brown, marked in radiating lines by the insertions of the mesenteries. The mouth is set on a darker-coloured prominent peristome, round which is a depression. There are two siphonoglyphs marked by pink tubercles. The structure of the disc recalls that of the tentacles, except that the nervous and muscular layers are not so well developed.

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Œsophagus.—The colour is a dull white, with brighter lines at the insertions of the mesenteries. Bourne* states that the sulcar and sulcular-siphonoglyphs do not differ in size and structure, but in my preparations one siphonoglyph appears much deeper than the other. This is a feature that frequently appears in sectioned anemones, and may be the result of treatment. On the other hand, it may mark the position of the sulcular-directives, which, being the first pair of directives, and having less to pull against than the second pair, may draw the stomodæum unduly towards-them. In my sections of L. thompsoni the deeper siphonoglyph is curiously folded, being bent on itself some six times almost at right angles. The cilia of this siphonoglyph are strong, and stained distinctly with hæma-toxylin.

Mesenteries.—There are 30 to 32 pairs, all perfect. Two pairs are directives (Plate XVIII, fig. 1). On all the mesenteries both retractor and parietal muscles are very strong; indeed, the whole animal is remarkable for its great muscular development. The central fold of the mesenterial trefoil stands well out beyond the lateral folds.

Gonads.—These appear in the usual place in the mesenteries. In one of the animals sectioned no ovaries appeared, but the body-cavity contained developing ova and embryos from the 2-chambered to the 12-rayed stage. It is interesting to note that one such embryo had 5 chambers. The young develop between the mesenteries until, at any rate, the 12-rayed stage is reached. They then appear to be ready for an independent existence, as I have found none beyond that stage in the body of the parent.

Dimensions.—A good specimen would be as much as 6–7 cm. in height and 4–5 cm. in breadth; tentacles, 2.5 cm.

Locality and Habits.—The species is apparently littoral, being found just above and below low-water mark, attached to the rocks and to loose stones. It is apparently fairly well distributed on the coast of New Zealand, but is not very numerous in any locality. It is more plentiful at Plimmerton than at any other place so far as I know. It has been found at most places-along the coast between Plimmerton and Wellington. Professor Coughtrey's specimens were found in Otago Harbour.

Sagartia albocincta.

This anemone was first described by Professor Hutton† as Gregoria albocincta. Gregoria was one of Gosse's genera of the family Sagartidæ. As it was erected for a single specimen, which Gosse himself thought might have been immature, and as no specimen has since been found, recent workers have agreed in dropping the genus. In reclassifying this animal I have adopted McMurrich's definition of Sagartia‡: “Sagartinœ with smooth column destitute of verrucæ, and with no special arrangement of the cinclides; margin tentaculate; tentacles concealed in contraction, the sphincter being fairly strong.”

Pedal-disc.—This only slightly exceeds the breadth of the column, and is about equal to the height. It is strongly adherent, and the animal can hardly be removed without damage. The usual histological structures are present. The three layers are all very thin, the mesoglœa especially so.

[Footnote] * “Treatise on Zoology,” ed. Ray Lankester, pt. ii, Anthozoa, p. 38.

[Footnote] † Trans. N.Z. Inst., vol. ii, 1878.

[Footnote] ‡ Proc. U.S. Nat. Mus., vol. xvi, p. 176.

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Column.—The shape is cylindrical. The colour is deposited in alternating vertical stripes, pink and white, pellucid brown and white, brown and yellow, or green and yellow. The upper part often assumes an orange, the lower a greenish tinge. In full expansion the body-wall is semi-transparent. The wall is pierced by a number of irregularly arranged cinclides, which are easily made out in a fresh specimen. They have thickened margins. The wall is traversed by longitudinal ridges, which appear in cross-sections as papillæ-like projections. Neither ectoderm nor endoderm present any departure from the ordinary structure. In sections, especially in longitudinal sections, the mesoglœa presents numerous spaces, each containing a deeply staining particle. There is a feebly developed circular muscle in the wall.

Tentacles.—These are all opaque, white, and rather fine. They are regularly arranged in four cycles, 12 + 12 + 24 + 48. They can be wholly retracted, though the favourite position of the animal when not distended is one in which the tentacles are partially withdrawn, the tips forming a white central mass. In shape the tentacles are conical and pointed. They are subequal, the longest being ½ to ¾ of the full diameter of the disc. The mesoglœa and endoderm of the tentacles are thin and the musculature weak. The nervous layer is well developed. Nematocysts are present.

Sphincter Muscle (Plate XX, fig. 3).—This is mesoglœal in character, and is represented by a clavate swelling of the mesoglœa. The thin end points downwards, and tapers off into the mesoglœa of the wall. In the thickened part run anastomosing strands of the supporting layer, forming irregular cavities, in which are seen the muscle-fibres, which here, consequently, are arranged in bundles.

Oral Disc.—The disc is bright orange in colour, with radial markings. The mouth is set on a peristome. On the inner side the mesoglœa bears short stout processes, giving it a notched appearance. The processes bear the endodermal or circular muscle of the disc. The ectodermal muscle is hardly perceptible.

Œsophagus.—The œsophagus is dull white, with brighter vertical lines. There are 2 siphonoglyphs, and sections show the œsophagus to be much folded. The mesoglœa is thick compared with that of other parts, and has a very striking reticular appearance, which recalls the structure of the sphincter.

Mesenteries (Plate XX, fig. 2).—These number 24 pairs, of which 2 pairs are directives. Of these 24 pairs, I take 6 pairs to belong to the first and 6 to the second cycle. These are all perfect, reaching the œsophagus, as also do some of the third cycle of 12 pairs. In addition, there are a few rudimentary mesenteries of a fourth cycle just showing. The retractor muscles on the perfect mesenteries are narrow, except on the directives, where they are strong, and placed close up to the œsophagus.

Acontia are emitted through the mouth and through the cinclides already mentioned. Some specimens emit the acontia much more reluctantly than others.

Gonads.—Only on one of the mesenteries did I see in my preparations any indication of a gonad—in this case an ovary.

Dimensions.—Height, 10–12 mm.; and diameter, 7–10 mm.

Habits and Locality.—This anemone is found on rocks, stones, and the roots of seaweed. It is very firmly attached, and can only be removed with difficulty. It opens freely in captivity. It is common in the neighbourhood of Wellington, and is also recorded from Lyttelton. Hutton's original specimens were found at Dunedin.

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Explanation Of Plates XVIII-XX.
Plate XVIII.

Fig. 1. Leiotealia thompsoni. Directive mesenteries, parts of four other mesenteries, body-wall, and siphonoglyph.

Fig. 2. Leiotealia thompsoni. Cross-section of sphincter muscle.

Plate XIX.

Fig. 1. Leiotealia thompsoni. Body-wall, showing the ridges into which the outer surface is thrown (cross-section).

Fig. 2. Leiotealia thompsoni. Body-wall, showing the mesoglœa pits lined by ectoderm.

Fig. 3. " Part of tentacle (cross-section).

Plate XX.

Fig. 1. Leiotealia thompsoni. Showing embryos developing within the body of the parent; one embryo at the “2-chambered” stage, the first pair of mesenteries just developing; the other advanced to the 12-mesenteried stage.

Fig. 2. Sagartia albocincta. Directive mesenteries.

Fig. 3. " Cross-section of sphincter.

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