Notes on Recent Papers dealing with the Mollusca of New Zealand.
[Issued separately, 23rd August, 1930.]
The following notes deal with nomenclatural confusion or erroneous location of species in certain papers which have lately appeared on our mollusca. The title and reference to each paper is given, and the points in it dealt with in order of their occurrence, the page being quoted to facilitate reference.
(1.) “The Geology and Palaeontology of the Lower Waihao Basin, South Canterbury, New Zealand.” By R. S. Allan. (Trans. N.Z. Inst., vol. 57, pp. 265-309; issued separately, Dec. 7, 1926).
In this paper Dr. Allan gives faunal lists of mollusca from the Waihao Downs, McCulloughs Bridge, and Mt. Harris. In the original form in which the paper was presented the generic locations current at the time were used. Since Dr. Allan had to depart for England, it was arranged that the proofs were to be sent to me for correction, and as my “Further Commentary” was to appear simultaneously I corrected the lists to agree with the changes in nomenclature proposed in that paper. When I returned the proofs I mentioned this to the Editor, and stressed the point that Dr. Allan's paper must on this account appear after mine. Somehow or other this was overlooked, and as a result we have long lists of mollusca with new generic names appearing before those genera were formally introduced. Such a piece of carelessness might have had much more serious results than it has, for fortunately nearly all the new names introduced in these lists are a sort of nomina nuda and can depend for their valid introduction only on the “Commentary.” For example, the list name “Zaclys (Miopila) tricincta (Marshall)” does not indicate whether the new names Zaclys and Miopila apply to Epitonium tricinctum Marshall, 1918, or to Cerithiella tricincta Marshall, 1919, while “Zexilia waihaoensis (Suter)” might apply to a form of Ampullina, Exilia, Pecten, or Rapana, Suter having given this specific name to a species described under each of these generic names from these same beds. As the lists are arranged in alphabetical order, no help is obtained from the relative position of the names. Consequently, unless further information is supplied, one must regard the quotation of a new generic name with a mere species name and author's name in brackets as indeterminable, and practically a genus caelebs.
The complete list of new names inadvertently introduced in this paper is as follows:—
Marshallena, with serotina (Suter) (p. 289), formosa (Allan), neozelanica (Suter), and spiralis (Allan) (p. 291).
Spirocolpus, with waihaoensis (Marwick) (p. 289).
Waimatea, with inconspicua (Hutt.) (pp. 289, 291), apicicostata (Suter), and opima Allan MS. (p. 291).
Notoseila, with attenuissima (M. & M.) (p. 291).
Proximitra, with parki (Allan) and plicatellum (M. & M.) (p. 291).
Zaclys (Miopila), with tricincta (Marshall) (p. 291).
Zeacolpus, with n. sp. (p. 291).
Zexilia, with crassicostata (Suter) and waihaoensis (Suter) (p. 291).
Maoricolpus, with cavershamensis (Harris) (p. 304).
Stiracolpus, with n. sp. (p. 304).
Venustas, with fragilis (Finlay) (p. 304).
Xymenella, with lepida (Suter) (p. 304).
Zeacrypta, with monoxyla (Lesson) (p. 304).
Coluzea, with dentata (Hutton) (p. 304).
All but two of these premature names can be disregarded; Marshallena and Coluzea, however, must be regarded as validly introduced on this occasion.
On p. 291, footnote, Allan notes that Marshallena neozelanica (Sut.) is Daphnella neozelanica Suter and equals Belophos incertus Marshall. That is sufficient to validate the name, and this species becomes the monotype of Marshallena Allan; fortunately I designated the same species as type when the later proposition appeared in the “Commentary,” 122 pages later.
The other case has not such a fortunate outcome. On p. 304 appears the line “Coluzea dentata (Hutton) (as Fusus).” This is again definite fixation of the generic name, so that Fusus dentatus Hutton becomes the monotype of Coluzea Allan, instead of the Recent spiralis A. Ad., for which I proposed the name 103 pages later. This, however, makes no difference in the conception of the genus.
One other alteration in this paper must be credited to Allan instead of to me. On p. 291, footnote, it is noted that “Turbonilla hampdenensis Finlay” is a new name for T. antiqua Marshall, preoccupied. The new specific name must, of course, be referred to Allan as author.
(2.) “Description of Two New Shells of Marine Gasteropod.” By C. E. R. Bucknill. (Trans. N.Z. Inst., vol. 58, pt. 3, pp. 311, 312; issued separately, Nov. 8, 1927).
Mayena multinodosa (p. 312). This seems to me better referable to Fusitriton Cossmann than to Mayena. It has every character of retiolum (Hedley) and laudandus Finlay except that the varices are regularly in line on opposite sides of the shell and are more strongly developed. But Mayena has not the varices in line either, and the other shell features agree well with Triton cancellatus Lk., the genotype, and the Californian oregonense (Redwood), which often shows varices almost in line on early whorls. Apart from the varices, multinodosa is well distinguished from laudandus by the character and
number of the spirals and I would regard it as a second Neozelanic species of Fusitriton.
(3.) “Some New Zealan Molluscs.” By Marjorie K. Mestayer. (Proc. Mal. Soc., Lond., vol. 17, pts. 5 and 6, pp. 185-190; Dec., 1927).
In this paper Miss Mestayer proposes six new specific names—every one of which is a synonym of a previously described species. Most of these had been named in my own “Further Commentary,” published Dec. 23, 1926, so that a full year elapsed before these redundant names appeared; ample time to withdraw them from publication. Such work is not helpful to science; we have enough nomenclatural problems in New Zealand without adding to them in this fashion. The time and money expended on this paper could have been more profitably employed. The synonyms are as follows:—
Brookula rexensis Mestayer (p. 185) is based on exactly the same specimen which I had previously named B. prognata (Trans. N.Z. Inst., vol. 57, p. 366; 1926).
Monodonta lugubris albina (p. 186) is a freak no more worth a name than an albino of any other species. I have seen red examples of Zediloma digna Finlay (= nigerrima auct.).
Triviella maoriensis (p. 186) is a perfect synonym of my T. memorata (l.c., p. 396), from the same locality, Ahipara Bay.
Triviella gamma (p. 188) is not only a synonym but also a foreign shell. Miss Mestayer informed me that the specimens were given to her by Suter, who probably obtained them by exchange and mixed them up with local shells. The species is one of the common tropical forms, probably pediculus Linn.; at all events there are shells so named in the foreign collection of the Dominion Muscum, which are identical in appearance and preservation.
Fusitriton futuristi (p. 189) cannot be separated as a species from my F. laudandum (Trans. N.Z. Inst., vol. 57, p. 399; Pl. 20, Fig. 65; Dec. 23, 1926). My species was described from 40 fathoms off Otago Heads; Miss Mestayer's is from 50-60 fathom off Cape Campbell, some 340 miles further north, and mine was stated to “differ in several respects from F. futuristi, the axials and spirals both being stronger, and the denticle weaker.” The denticle is of no specific importance, and Miss Mestayer's figure shows sculpture equal in prominence to laudandum. It is difficult enough to distinguish laudandum from the Australian retiolum Hedley, without attempting to separate a second New Zealand species of this type. both being known from single specimens. As I have just noted, I regard Mayena multinodosa Bucknill as a second New Zealand species of Fusitriton, but it is of a different type in its variceal development.
Pecten (Cyclopecten) hinemoa (p. 190) is again proposed for the identical specimen which I had named Cyclochlamys secundus (l.c., p. 453).
(4.) “Notes on New Zealand Mollusca.” No. 4. By Marjorie K. Mestayer. (Trans. N.Z. Inst., vol. 60, pt. 2, pp. 247-250; issued separately, Aug. 15, 1929).
The practice adopted in this paper of writing all specific names with capitals does not seem an improvement on the existing system;
besides being in direct contravention of Article 13 of the International Rules of Zoological Nomenclature.
Pallium kapitiensis, described in this paper (p. 249), is certainly a synonym of the common Pecten convexus Q. & G. Supposed differences in the ribbing and posterior ear are pointed out, but these are quite variable. It is impossible to distinguish two satisfactory forms of this species; the flatter shells usually have broad, low, radial ribs with sublinear interstices, while the very convex shells have generally more numerous thin and sharp radials with wider interspaces, but neither form is constant, and the sculpture may change from one type to the other on the same valve, following a rest period and inturning of the shell. All my Chatham Island valves are of the flat broadly ribbed type, but off Otago Heads in 60 fathoms occur numerous valves showing every gradation and interchange of the two types. The flatter valves are mostly like the Chatham shells, but merge gradually into extremely convex and inflated shells, with ribbing exactly like Miss Mestayer's type—which she states is rather flattened. Furthermore, exactly the same variation and intergrading of the two types is found in Tertiary ancestral forms, the Miocene burnetti Zittel, etc., being exactly comparable to convexus in this respect.
There are enough very distinct new species to describe in New Zealand without creating synonyms in this fashion.
(5.) “Tertiary and Recent Volutidae of New Zealand.” By J. Marwick. (Trans. N.Z. Inst., vol. 55, pp. 259-303; issued separately, March 13, 1926).
This fine monograph gives for the first time an adequate account of the New Zealand Volutidae. Although the classification adopted is in the main perfectly satisfactory, there are one or two minor points which I think might receive further attention. A large number of the species were described from my collection, which is fairly complete in the group except for some Pliocene species, and I have had occasion several times to go over critically several of Marwick's groupings. Therefore, with due deference to his opinion, as that of an expert who has given much study to the group, I suggest the following changes and occasionally re-groupings as being, in my opinion, more natural.
Genus Mauia (p. 271). This is a compact assemblage with the exception of M. insignis Marwick (p. 274), which is also widely sundered from the other (early Tertiary) members in age, being a Pliocene shell. It has much more prominent and numerous axial ribs, which extend from suture to basal fasciole, and a peculiarly ascending and channelled outer lip where it joins the parietal wall. It is difficult to say whether it is allied more closely to Mauia or to Pachymelon. My personal opinion is that Mauia became extinct soon after the development of increasing geronticism and size in its latest members, curvispina and huttoni, and that the deep anterior notch of insignis indicates either a throw-off from the Alcithoe line, or, more probably, an evolution from Pachymelon. Taking this view, I propose to separate Mauia insignis Marwick by naming it as type of a new genus Mauithoe.
With it I feel inclined to associate Alcithoe parva Marwick (p. 301), described from Kaawa Creek. Alcithoe propearabicula Bartrum and Powell (Trans. N.Z. Inst., vol. 59, p. 148; Fig. 61; May 24, 1928) is, I feel sure, a synonym of this species, coming from the same locality, and the figures and descriptions agreeing in every detail. All the principal features of Mauithoe seem to be shown by this Waitotaran species, while Alcithoe dilatata Marwick (p. 301) is a species certainly congeneric with parva, and may also be located here. These two species seem to be descended from Mauia stock rather than on the Alcithoe line, and though shorter in the shell than insignis may be genetically associated with it at present.
Sub-genus Pachymelon (p. 281).—My conception of Marwick's genus Waihaoia and this subgenus differ a little from his. Specimens in my collection indicate that Waihaoia and Teremelon were barely distinct in Tahuian times (though abundantly so later), but that Waihaoia was earlier developed, being well established in Bortonian beds. In the Hutchinsonian, Pachymelon was just evolving from Waihaoia. After Marwick's account was written, I collected several more species of this group in the Clifden beds, and certain forms from beds 7 and 8 seem to indicate quite definitely the transition stages between Waihaoia, which is common in beds 4 and 6, and Pachymelon, which predominates in beds 7 and 8. Adult examples, for instance, from bed 8 show that my Alcithoe regularis, which Marwick referred to Waihaoia, is really a Pachymelon, growing much wider, thicker, heavier, and shorter in the spire than the juvenile type would lead one to suppose. Bearing this in mind, I would also refer Waihaoia dyscrita (Finlay) (p. 276) to Pachymelon, as a transitional form; no further specimens have been found.
Turning now to the species included by Marwick (p. 281) in Pachymelon, I note that the Recent lutea (Watson) (p. 282) has already been extracted from this association and made the monotype of Palomelon Finlay (Trans. N.Z. Inst., vol. 57, p. 432; Dec. 23, 1926). Powell, in his list of our Recent Volutidae (l.c., vol. 59, p. 364; Aug. 30, 1928), has overlooked this, also my reference of Microvoluta biconica (Murd. & Suter) to the Volutidae (l.c., vol. 57, p. 410).
Waihaoia (Pachymelon) waitakiensis Marwick (p. 281) may also be removed from this neighbourhood; it is a Spinomelon, and a synonym of S. benitens (Finlay). I have a topotype from Wharekuri identical with waitakiensis, and this offers no separative characters from the smooth benitens, which is from beds not far above. This is the only one of Marwick's species with four plaits on the pillar, so I would amend his subgeneric diagnosis to read “Columella produced, generally with 5 folds, occasionally 6, never 4.”
Waihaoia (Pachymelon) renwicki Marwick (Trans. N.Z. Inst., vol. 58, p. 488, Fig. 147; Feb. 28, 1928), from Whenuataru Peninsula, Chatham Island Tertiaries, has also now to be added to the list of species.
Genera Spinomelon (p. 283) and Metamelon (p. 285).—Although the great mass of our Volutes have a secondary scaphelloid nucleus, i.e., not originally shelly, and therefore roughened and variable in
form, only Spinomelon and Metamelon of all our groups have a sharp caricelloid apex, with a strong spike. Even apical fragments can be with certainty referred to these genera, and it becomes a matter of importance to distinguish between them when juvenile. Marwick has not made this clear, but it can be done with the smallest fragments, if the embryo is complete. The apex of Metamelon is always narrow and tall and followed by smooth spire whorls, sculpture developing later, if at all; that of Spinomelon is in a few aberrant forms somewhat like that of Alcithoe, globose and rounded with not much indication of a spike, but is typically strongly spiked and always considerably wider than that of Metamelon, shorter and larger, and followed by costate spire whorls, sculpture obsolete only occasionally on the last whorls; both genera agree in the roughened first volution and spike, and smooth second volution with 2-4 irregular thread-like keels.
As regards the species of Spinomelon, I have just noted that Pachymelon waitakiensis Marwick is a synonym of benitens (Finlay). Alcithoe residua Finlay (p. 301), as Marwick thought, shows much stronger affinity to Spinomelon than to Alcithoe; having seen some similar new species, I now refer it definitely to that genus as a somewhat aberrant line. One other addition is Fulgoraria (Alcithoe) arabica var. turrita Suter, which Marwick (p. 288) included as an early member of Alcithoe. I have some perfect apices from Blue Cliffs (the type locality) which show the characteristic sculpture and whorl shape of turrita, but have the spike and other embryonic features of Spinomelon. They are not parki, and answer only to Suter's species. It is easy, too, to see the natural affinity between speighti and turrita as shown by Marwick's figures (Pl. 64, Fig. 7 and Pl. 66, Fig. 8); turrita is a good species of Spinomelon, chiefly characterised by its high spire. This leaves the earliest Alcithoe as wekaensis Marwick (p. 288), which is by no means typical. I am inclined to think that some at least of the Alcithoes arose from Spinomelon.
Metamelon minima (p. 287).—The type is from Mt. Harris, not Otiake as given by Marwick. It is a curious form, but seems best placed here.
(6.) “Mollusca from Kaawa Creek Beds, West Coast, South of Waikato River.” By J. A. Bartrum and A. W. B. Powell. (Trans. N.Z. Inst., vol. 59, pt. 1, pp. 139-162; issued separately May 24, 1928).
In this paper several of the names proposed by me in the “Further Commentary” are rejected. In subsequent correspondence the authors have admitted that in some cases their reasons for rejection were insufficient, while in others I had not made myself clear enough in defining the groups (e.g., Zelandiella, for the subsequent acceptance of which as a distinct genus see Powell, Trans. N.Z. Inst., vol. 60, p. 93; 1929).
Some of the species described or recorded require comment, as follows:—
Spectamen cf. egena (p. 140).—“Finlay …., anticipating distinctive radular characteristics, has introduced a new generic name Antisolarium.” This is incorrect; reference to my original proposi-
sition (Trans. N.Z. Inst., vol. 57, p. 359 and 360; Dec. 23, 1926) of Antisolarium, Zeminolia, Zetela, and Conominolia will show that these four groups were proposed on shell characters. It is sufficient to quote the following, which seems to me clear enough: “It is quite impossible, therefore, to forecast the radular features of the Neozelanic series, and as they disagree conchologically with Australian shells, I consider the correct course to pursue is to propose new names for the different groups met with in New Zealand, and wait until the animal characters are available to ascertain definitely their generic or subgeneric value.” Spectamen is an impossible location for egena, for it has a different protoconch, shell formation, and aperture. A tiny inconspicuous embryo like that of Antisolarium and Conominolia is shown only by Ethminolia of the Australian groups, but this has the shell features and aperture of Spectamen (but of course a different radula, while the characteristic habit and aperture of egena are well shown in the figure given by Cossmann (Ess. Pal. Comp., livr. 11; Pl. 8, Figs. 57, 58—as zelandica Hutt.). As I stated before, Antisolarium rather recalls Solariella in shell features, though it may be noted that Cossmann, dealing with all these forms, did not associate it with Solariella, but with Conotrochus Pilsbry (l.c., p. 262), indicating a definite distinction even here. A large and bulbous embryo distinguishes the groups Zeminolia and Zetela, and the Australian groups Spectamen and Minolia, though in the two latter it is not so disproportionately developed. Of all the New Zealand groups Zeminolia is most like Spectamen, but has a still more open umbilicus, and larger embryo; the two forms are more distinct than are Spectamen philippensis and Ethminolia probabilis, which have quite different radulae, and I consider it misleading to group them together. In view of the complex relationships of these shells, and the unavailability of the radula in Tertiary forms and many Recent ones, I would lay it down as a fixed principle that no two Minolioids can be generically associated whose protoconchs do not exactly agree; whatever the radulae of the New Zealand species turn out to be when investigated, I would still separate them from the Australian series on shell and embryonic differences alone.
Turbo postulatus Bartrum (p. 141).—A detailed discussion of this shell and the interesting problems it raises is given in a separate paper in this volume.
Struthiolaria (p. 142).—Of the three new species proposed here, arthritica is a Callusaria—one of the last of the group—and pseudovermis is a Pelicaria.
In the “Further Commentary” (p. 391) I provided Callusaria for the four species included by Marwick (Trans. N.Z. Inst., vol. 55, pp. 182-184; June 6, 1924) in his “Struthiolaria callosa group.” I would now extend its limits, and class the following succession of species in Callusaria: obesa Hutton, arthritica Bartrum and Powell, fortis Marwick, armata Marwick, callosa Marwick, spinifera Marwick, spinosa Hector, and tuberculata Hutton. To my mind these form a compact assembly, agreeing in apex, but differing in shell and spine formation, and somewhat in aperture, from Struthiolaria s. str., under which I would range papulosa Martyn, frazeri Hector, errata Marwick,
cingulata Zittel, illepida Bart. and Powell, cincta Hutton, praenuntia Marwick, calcar Hutton, subspinosa Marwick, and prior Finlay.
Genus Crypta (p. 144).—“Finlay …., apparently on the basis of anticipated differences in the radula of New Zealand shells from those of Crepidulids of other areas, creates a new genus Maoricrypta.” This again is a mis-reading of my account (Trans. N.Z. Inst., vol. 57, p. 393; Dec. 23, 1926); I pointed out valid shell differences between Maoricrypta and Crypta, and these have since been substantiated by Marwick (l.c., vol. 59, p. 918; March 25, 1929).
Xenophalium (p. 145).—In this paper and elsewhere Powell argues that Xenogalea Iredale is a synonym of Xenophalium Iredale, and classes all our species of pyrum affinity under the latter name. I disagree with this. Xenogalea is a compact association of species, and hedleyi Iredale and royana Iredale cannot be forced into it without destroying its unanimity. Powell later (Trans. N.Z. Inst., vol. 50, p. 635; Nov. 23, 1928) writes that “Iredale in defining the first-mentioned genus stated that it was characterised by large size and open unarmed mouth. This latter feature is also common to most of the species of his second genus Xenogalea, leaving the larger size as the only distinguishing character. This feature alone is hardly sufficient justification for creating a new genus…” Everyone who has worked in Natural Science knows how difficult it is to define exactly in words the precise differences between convenient genera in large groups of similar forms. Iredale does not err on the side of verbosity, but his conceptions of genera seem very natural, and in the present case his separation of hedleyi from the common forms appears to me quite justified. Powell's own figures of royana (l.c., Pl. 74, Figs. 11, 12) have a different look from all his figures of Xenogalea, though it is not easy to put the difference into words. But the characteristic style of nodulation, the high spire, the long body-whorl, not inflated anteriorly, and the straight hardly-wrinkled pillar, combined, as Iredale says, with large size and open unarmed mouth, sufficiently differentiate this species, hedleyi Iredale, and probably wyvillei Watson from true Xenogalea. I would suggest that there is at least as much difference between these two groups as between the species harrisonae Powell and multisecta Finlay, which Powell places in different genera.
Alcithoe propearabicula (p. 148).—I have already noted that I think this is a synonym of Mauithoe parva (Marwick, 1926), from the same locality.
Genus Austrodrillia (p. 150).—The reasons given for the merging of Splendrillia Hedley with the same writer's Austrodrillia are not very convincing, being merely May's reference, in a list of species, of woodsi (genotype of Splendrillia) to Austrodrillia—possibly inadvertently. Austrodrillia is easily distinguished from Splendrillia by its simple outer lip and sinus.
Semeloidea donaciformis (p. 158).—This new genus was compared by its authors to Donax and, more closely, to Semele. But it is evidently a member of the Erycinidae, allied to Myllitella, Zemyllita, Rochefortula, etc. This was my impression from the figures, and actual specimens I have since seen confirms it. Compare such a
species as Bornia lioica Dall (Tert. Fauna Florida, pt. 4; Pl. 25, Fig. 6) from the Caloosahatchie Pliocene, which is of the same style and shows similar sulcations.
(7.) “Tertiary Molluscan Fauna of Chatton, Southland.” By J. Marwick. (Trans. N.Z. Inst., vol. 59, pt. 4, pp. 903-934; issued separately, Mar. 25, 1929).
One or two of the species described in this paper call for comment.
Cyclopecten compitum (p. 909).—This is not a Cyclopecten, but a nepionic Chlamys with merely the beginning of the adult sculpture. No Cyclopecten has this irregular ornament, but every Chlamys starts off more or less in this fashion. Enough of the adult sculpture is developed to show that the species is of the chathamensis type, and is the same as that occurring commonly in the Wharekuri greensands. I have one half-grown shell from Chatton which corresponds at the umbo with compitum, and is exactly the same as Wharekuri shells. As I intended describing this form, I now present the photographs I had taken (Figs. 1, 2) of Wharekuri specimens, to show the normal adult appearance of the species. It is easily distinguished by its very even and regular sculpture of stout rounded radial ribs, rather distant and lamellose, the interstices 1½-2 times their width and quite smooth.
This also seems the best place to point out that Marwick, in his “Summary of New Zealand Pectinidae” (Trans. N.Z. Inst., vol. 58, p. 453; 1928) has omitted the following four species from the genus Chlamys:—zelandiae Gray, 1843; subantarctica Hedley, 1916 (Macquarie Island); williamsoni Zittel, 1865 (Tertiary: Aotea, Auckland); and grangei Murdoch, 1924 (Upper Cretaceous; Brighton belemnite beds). To these compitum has also now to be added.
Genus Chattonia Marwick (p. 909). Type: C. animula n. sp.—This is a synonym of Salaputium Iredale (Proc. Linn. Soc. N.S.W., vol. 49, pt. 3, p. 204; Oct. 24, 1924); type: Crassatella fulvida Ang. I noted in the “Further Commentary” (p. 458) that “Salaputium Iredale, given to a large series of Australian minute forms, has as yet no Neozelanic representative.” C. animula, however, undoubtedly belongs to this group; it has smooth margins, but I now have another new species from Pakaurangi Point which has crenulated margins; the Australian forms are very numerous, and have both smooth and crenulated margins. They seem to be arrested stages in the development of the Crassatellites and Spissatella groups, and are often with difficulty separable from juveniles of the larger species. Animula occurs at Chatton in company with Spissatella poroleda Finlay, and also at Wharekuri with S. subobesa (M. & M.), but has uniformly denser sculpture, not smooth in the brephic stage, and a slightly different shape and hinge; it is truly adult and was rightly distinguished by Marwick. The new genus he made for it, however, must fall in synonymy.
Pholadidea increnata (p. 914).—I suggest that this is a synonym of Martesia concentrica Suter, 1917 (N.Z.G.S. Pal. Bull. No. 5, p. 79; Pl. 13, Fig. 9), from the lower tuffs, Broken River, Trelissick Basin. They are from approximately coaeval horizons, which are in both cases fairly shallow water beds. Dr. Marwick's shell is twice the size
of Suter's, but otherwise no difference is observable. Both have a deep submedian furrow, strong concentric sculpture which is more lamellose anteriorly, a small anterior gape, no sign of callus plates, and are identical in shape.
Neither Suter's location in Martesia, nor Marwick's in Pholadidea can be upheld. Suter was influenced by the appearance on the posterior dorsal margin of a “a fairly large semioval sinus which is no doubt the place occupied by the protoplax.” On account of the condition and preservation of the specimen, and Suter's many other errors of observation in this Bulletin, one may doubt the correctness of his inference; increnata shows no sign of this formation, and in any case the other shell characters are quite at variance with Martesia. The shape and extent of the anterior part of the shell alone make reference here impossible. Martesia and Pholadidea are both genera of Tryon's Subfamily Jouannetinae, distinguished, according to Dall (Tert. Fauna Florida, pt. 4, p. 818; 1898) by having the “Anterior gape closed in the adult by a calcareous deposit attached to either valve, and the edges of which meet in the middle line below; valves with one or more radial sulci, and with one or more accessory plates.” The Subfamily Pholadinae, on the other hand, has the “Anterior hiatus permanently open, with no callum.” It seems evident from the descriptions and figures of concentrica and increnata that they belong to the latter Subfamily; in this the median groove is an exception and is paralleled only by Zirfaea (Leach) Gray. That genus, however, has a large anterior gape, and the anterior end of the valve is shaped like Barnea, not regularly convex. Talona Gray has the front gape small, and a regularly rounded anterior end, but has strong radial sculpture and no groove. I can find no group to which the New Zealand form can be satisfactorily referred, so now propose
Zirlona n. gen; with type, Pholadidea increnata Marwick. A genus of the Pholadidae (Subfamily Pholadinae), with a small anterior gape, no callus plates closing the shell in front, but the anterior ends of the valves more or less rounded and approximating; a submedian deep oblique groove dividing the valves, the anterior portion bearing strong regularly spaced unsinuated concentric lamellae, but faintly crenulated, the posterior portion bearing low broad regular concentric folds; no radial sculpture; the dorsal margin somewhat concave and reflexed. Accessory plates unknown.
Although I think that there is but one New Zealand species so far known, and propose to call it Zirlona concentrica (Suter), I have named increnata as type since it is much the better preserved specimen, and may possibly prove distinguishable when more than one specimen from each locality is collected. Also, I have not seen either specimen, but am basing these notes on the figures and descriptions.
Tate (Proc. Roy. Soc. N.S.W., vol. 31, p. 409; Pl. 20, Fig. 7a, b; 1897) has described an Australian Miocene species, found burrowing in coral, as Martesia elegantula, and indeed this seems much more like Martesia, and quite unlike the New Zealand form.
A true Tertiary species of Pholadidea has been described by Suter as P. thomsoni (N.Z.G.S. Pal. Bull. No. 5, p. 78; Pl. 10, Fig. 9; 1917) from Anthony Bay, Hauraki Peninsula, Auckland, found boring
in shells of Ostrea wuellerstorfi Zitt. This seems the best place to record that I have obtained several specimens of the same species from Muddy Terrace, Waikaia, Southland, in exactly the same situation, only the host in this case was O. wollastoni Finlay. It is a well-marked form, with a very prominent callus closure in front, nearest, as Suter says, to tridens (Gray). Of this Recent species I have but one example, but this is abundantly distinct in shape and anterior ornament from spathulata (Sow.).
Antisolarium vixincisum (p. 915).—This is a Conominolia, not an Antisolarium; I can record it also from Muddy Terrace, Waikaia. Conominolia is always more elevated than Antisolarium (though stoliczkai is getting tall), has more deeply cut-in sutures (i.e., whorls do not overlap), has many more or less equal spirals instead of a few very strong ridges, and has a thread in the umbilicus. This species has a striking superficial resemblance to Philippia lutea in miniature.
Elachorbis duplicarina (p. 915).—Dr. Marwick states that “The classification under Elachorbis is only provisional, for the two strong keels are not present in that genus.” The Miocene Cyclostrema helicoides Hutton, from White Rock River, however, shows prominent keels, yet its genetic connection with the Recent Australian tatei Angas, through such Tertiary forms as politus Suter and cingulatus Bartrum and the Recent New Zealand subtatei Suter seems indisputable. Possibly two series are represented, but they all have the same embryo and aperture.
Proximitra incisula (p. 920).—This is a synonym of P. ligata (Suter) (N.Z.G.S. Pal. Bull. No. 5, p. 28; Pl. 4, Fig. 9), described as a Vexillum, from Wharekuri. So many of the Chatton and Wharekuri forms are identical that the occurrence of two Proximitras of this style is improbable, and my own specimens show that the correspondence is exact. Suter's type of ligatum is a small shell (9 by 4 mm.), but my largest specimen measures 14 by 6.2 mm., while Marwick's type is 12.5 by 6 mm. These dimensions indicate similar proportions, and the whole of Marwick's description applies exactly to ligatum; his distinguishing features hold good when applied to any other species, but not to this one.
I would refer Mitra (Cancilla) armorica Suter (N.Z.G.S. Pal. Bull. No. 5, p. 27; Pl. 12, Fig. 4) also to Proximitra as a close relative of rutidoloma the genotype (which occurs with it), but of smoother habit and less quadrate whorls; the embryonic features and aperture are identical. I did not refer to this species in the “Further Commentary,” but gave figures of Otiake specimens in Trans. N.Z. Inst., vol. 55, p. 468; Pl. 50, Figs. 4a, b.
New names proposed in this paper:—
Mauithoe n. gen. Type: Mauia insignis Marwick.
Zirlona n. gen. Type: Pholadidea increnata Marwick.