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Volume 47, 1914
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Siphonaria.

The representatives of this genus in the Kermadec Islands recall Cellana in the multiplicity of forms and the difficulty of dividing them into specific groups with satisfactory limits. I have a good series of specimens from Sunday Island, Macauley Island, and French Rock, and on comparing them with what specimens are available to me from Norfolk Island, New Zealand, Australia, and Tasmania I find that all appear to be distinct from the species of those countries. The chief affinities lie with Norfolk Island and New Zealand. I separate the Kermadec specimens into four species. Here, as in Cellana, there seems to be some relation between specific divergence on the one hand, and habitat and distribution on the other, for the three principal species found at Sunday Island affect distinct habitats, while the dominant forms on Macauley Island and French Rock differ from each other and from those on Sunday Island. Hiding in crevices of rocks near high-water mark on Sunday Island is the small S. amphibia; lower down the high and polished S. raoulensis occurs; while near low-water mark is found abundantly the remarkable S. cheesemani, usually coated with crustaceous algae, and often adhering to the great shells of Scutellastra kermadecensis.

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Siphonaria raoulensis n. sp. Figs. 40 and 40a.

Recorded, Suter, Trans. N.Z. Inst., 39, 265 (S. diemenensis).

Description of Type Specimen.—Shell ovate-elliptical, conoidal, height 0.39 of length. Right side straight in centre, then rather sharply turning to either end. Apex a little behind the centre, directed backwards and to the left. Anterior slope slightly arched, posterior nearly straight. Margin fairly regular and crenulated, chiefly on the right side. Siphonal groove not prominent. Sculpture: There are about 40 rounded smooth and polished radiating ribs. These are irregular in size, the larger ones being chiefly on the posterior slope, while there are 2 prominent ones on the siphonal groove. Colour: Bluish, darker towards the centre, the ribs nearly white, especially near the margin. Interior light-bluish, the margin nearly black, with white transverse bands opposite the ribs. At the siphonal groove 2 white bands extend about half-way towards the apex.

Length, 18 mm. Breadth, 12.8 mm. Height, 7 mm.

Variations from Type.—The ribs vary somewhat in prominence, and the general shape of the shell is liable to variation, as will be seen by the following measurements: (a.) Length, 19.6 mm.; breadth, 15.6 mm.; height, 6.4 mm.; ratio height to length (L. = 100), 0.31. (b.) Length, 19.8 mm.; breadth, 14.5 mm.; height, 7 mm.; ratio height to length, 0.28. (c.) Length, 17 mm.; breadth, 13 mm.; height, 7 mm.; ratio height to length, 0.24. The colour varies somewhat. The interior is sometimes nearly white or yellowish, with a black-banded margin. The apex is occasionally eroded and whitish. Most of my specimens were collected on rocks adjoining sandy beaches, and show the effects of sand-rubbing in their highly polished surfaces.

Habitat.—Living on rocks between tide-marks, Sunday Island; plentiful in places.

Siphonaria cheesemani n. sp. Figs. 41 and 41a.

Description of Type Specimen.—Shell elliptical, slightly narrowed in front, very depressed, height 0.21 of length, slopes nearly straight. Margin deeply incised, the principal ribs projecting to a distance equal to their width, slightly crenulated between the projecting ribs. Siphonal groove a double rib, but not more prominent or projecting further than the other large ribs. Sculpture: There are 13 high rounded radiating ridges, each projecting beyond the margin. The anterior ridges slightly smaller than the posterior. Ridges irregularly spaced, the largest interstice being behind the siphonal groove, the second-largest immediately posteriorly to this. Between the principal ribs are smaller riblets, chiefly noticeable on the right side. The whole upper surface covered with crustaceous algae, apex eroded. Colour: Interior nearly black, with a central white spot. Margin darker, with white bands opposite the ribs and riblets.

Length, 17.3 mm. Breadth between parallels touching the ribs, 13.5 mm. Height, 3.7 mm.

Variations from Type.—There being no adult specimens collected that were not covered with algae, I am obliged to add the following particulars from a smaller beach specimen: Apex situated behind and to the left of the centre and directed away from the centre. Between the principal ribs are fine close riblets. Concentric growth-lines show over the whole surface.

The number of principal ribs varies in different shells, being usually more than in the type, while the anterior ribs are frequently smaller and more numerous than in the type.

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Habitat.—Abundant living on rocks near low-water mark, Sunday Island. The shells almost always covered with crustaceous algae, and sometimes found attached to shells of Scutellastra kermadecensis. In its depressed form it resembles a number of marine molluscs inhabiting the lowest portion of the littoral belt.

Siphonaria macauleyensis n. sp. Figs. 42 and 42a.

Description of Type Specimen.—Shell irregularly ovate, high, conical, height 0.48 of length. Anterior slope long, arched; posterior slope steep, nearly straight. Apex nearly two-thirds the length of the shell from the anterior end, and to the left of the central line, directed backwards. Margin fairly regularly crenulated. Siphonal groove scarcely projecting. Sculpture: About 45 close nearly regular radiating ribs, two on the siphonal groove and a few others here and there on the posterior half larger than the others. All crossed by concentric growth-lines. Colour: Above grey, the ribs nearly white. Interior whitish in the centre, muscle-impression brown, followed by a whitish band and a dark-brown margin crossed by white bands opposite the ribs.

Length, 19.6 mm. Breadth, 14.6 mm. Height, 9.5 mm.

Variations from Type.—There is a good amount of variation in the shape of the shell, prominence of the ribs, and especially of the siphonal groove, which sometimes projects a considerable distance. When this is the case with depressed forms they come very close to the subspecies perplexa. The depth of colour inside varies, some examples having the central portion all brown. The following measurements show variations in the shells: (a.) Length, 19.5 mm.; breadth, 16.2 mm.; height, 10 mm.; ratio height to length (L.= 100), 0.51. (b.) Length, 19.3 mm.; breadth (behind siphonal groove), 15.5 mm.; height, 6.2 mm.; ratio height to length, 0.32.

A few specimens which I collected on French Rock apparently belong to this species. They are larger than those from Macauley Island, and all have the upper surface either corroded or covered by coralline algae, so that the sculpture is obscured. The general shape and the colour of the interior, however, agrees with Macauley Island specimens. Length, 23 mm.; breadth, 18.5 mm.; height, 8.3 mm.

S. macauleyensis comes very close to S. exulorum from Norfolk Island, differing principally in the more irregular shape and ribbing, and in the more posterior position of the apex. S. zealandica is also allied, but easily distinguishable from the above two.

Habitat.—Living on rocks between tide-marks, Macauley Island (type locality) and French Rock; common. A few specimens were also obtained on Sunday Island.

Subsp. perplexa n. subsp. Figs. 43 and 43a.

Recorded, Iredale, Pro. Mal. Soc., ix, 71, 1910 (S. atra).

Description of Type Specimen.—Shell depressed, height 0.29 of length, ovate, left side slightly rounded in the centre, sloping sharply away at either end, right side semicircular. Apex subcentral. Slopes slightly arched. Margin irregularly crenulated. Siphonal groove high, angular, and projecting for a distance equal to one-third of that between margin and apex. Sculpture: Irregularly spaced straight or wavy radiating ribs, about 20 principal ones, including 2 on the siphonal groove. They are of various sizes, those on the left side and alternate ones on the posterior half

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being larger than the others. There are smaller riblets in the interstices, including those on the siphonal groove and a wide space between it and the next posterior large rib. Colour: Above bluish-grey, the ribs nearly white. Apex corroded. Interior bluish-brown, the margin darker, and with numerous white cross-bands opposite the ribs.

Length, 17.3 mm. Breadth behind siphonal groove, 13.2 mm. Height, 5 mm.

The type specimen of this subspecies differs considerably from that of the typical subspecies, but intermediate forms which might be referable to either are common, so that I could not divide them satisfactorily into two groups, hence the present arrangement under one species. S. cheesemani also in some of its forms approaches the subspecies perplexa.

Habitat.—Living on rocks near low-water mark, Sunday Island.

Siphonaria amphibia n. sp. Fig. 44.

Description of Type Specimen.—Shell small, ovate, narrowed in front, conoidal, height 0.35 of length. Apex behind the centre, anterior slope slightly curved, posterior slope straight. Margin irregular, siphonal groove slightly projecting. Sculpture: The upper half of the shell corroded. Margin with about 25 scarcely raised radiating ribs. Colour brown, the ribs white. Interior black, the margin crossed by white bands opposite the ribs.

Length, 7.8 mm. Breadth, 6.2 mm. Height, 2.7 mm.

Variations from Type.—Most of the shells have the interior entirely black, and in many the entire upper surface is corroded.

Habitat.—This little species was found living in crevices and irregularities of rocks near high-water mark at Fleetwood Bluff, Sunday Island. In size, appearance, and habits it resembles some small species of Acmaea which occur in similar situations in New Zealand.

Gadinia conica Angas

Gadinia conica Angas, Pro. Zool. Soc., 1867, 115, 1868.

Recorded, Iredale, Pro. Mal. Soc., ix, 71, 1910.

Habitat.—Living on rocks between tide-marks, Sunday Island.

Distribution.—New Zealand, Australia.

Helicarion kermadecensis (Smith).

Vitrina kermadecensis E. A. Smith, Ann. Mag. Nat. Hist. (4), xi, 288, 1873.

Recorded, E. A. Smith, l.c.

Habitat.—Living on the under-surfaces of the leaves of the nikau palm (Rhopalostylis Baueri) on the summit of Moumoukai, the highest point of Sunday Island. Found only during wet weather, October. 1908. Also found living under dead leaves on the ground.

Ptychodon royanus Iredale.

Ptychodon royanus Iredale, Pro. Mal. Soc., x, 377, 1913.

Recorded, Iredale, l.c.

Habitat.—Living on the moss-covered trunks of trees, Sunday Island.

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Ptychodon pseutes Iredale.

Ptychodon pseutes Iredale, Pro. Mal. Soc., x, 378, 1913.

Recorded, Iredale, l.c.

Habitat.—Living on the ground under stones, rotten wood, and dead palm-leaves, Sunday Island.

Ptychodon amandus Iredale.

Ptychodon amandus Iredale, Pro. Mal. Soc., x, 378, 1913.

Recorded, Iredale, l.c.

Habitat.—Living on the ground under stones, wood, and dead palmleaves, Sunday Island.

Charopa macgillivrayana Iredale.

Charopa macgillivrayana Iredale, Pro. Mal. Soc., x, 379, 1913.

Recorded, Iredale, l.c.

Habitat.—Living on the ground under stones, wood, and leaves on high land only, Sunday Island.

Charopa exquisita Iredale.

Charopa exquisita Iredale, Pro. Mal. Soc., x, 379, 1913.

Recorded, Iredale, l.c.

Habitat.—Living on the ground under stones, wood, and leaves, Sunday Island.

Charopa pseudanguicula Iredale.

Charopa pseudanguicula Iredale, Pro. Mal. Soc., x, 380, 1913.

Recorded, Iredale, l.c

Habitat.—Living on the moss-covered trunks of trees, Sunday Island.

Flammulina miserabilis Iredale.

Flammulina miserabilis Iredale, Pro. Mal. Soc., x, 383, 1913.

Recorded, Iredale, l.c.

Habitat.—Living on moss-covered trunks of trees, Sunday Island.

Paralaoma raoulensis Iredale.

Paralaoma raoulensis Iredale, Pro. Mal. Soc., x, 381, 1913.

Recorded, Iredale, l.c.

Iredale describes a second species of Paralaoma from Sunday Island. I have some hundreds of specimens, which, though the number of lamellae varies, can scarcely be separated into two definable groups. I therefore treat his species as subspecies, which, using his diagnoses, may be thus defined:—

Subsp. typica.—Periphery rounded, lamellae on last whorl usually exceeding 40.

Subsp. ambigua (Iredale).—Periphery semi-keeled, lamellae on last whorl usually less than 30.

Habitat.—Living on the ground under stones, rotten wood, and dead leaves, Sunday Island.

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Calymna arboricola Iredale.

Calymna arboricola Iredale, Pro. Mal. Soc., x, 383, 1913.

Recorded, Iredale, l.c.

Habitat.—Living on moss-covered trunks of trees, Sunday Island.

Fanulum expositum (Mousson).

Trochonanina exposita Mousson, Journ. de Conch., xxi, 111, 1873.

Recorded, Mousson, l.c.

Var. moumoumkai Iredale.—Shell yellowish-white. Single specimens only found. Possibly these are albinos. I think they scarcely justify a name.

Habitat.—Living on the ground under rotten palm-leaves in scattered colonies on the higher ground only, Sunday Island.

Kieconcha kermadeci (Pfeiffer).

Helix kermandeci Pfeiffer, Pro. Zool. Soc., 1856, 326, 1857.

Recorded, Pfeiffer, l.c.

Habitat.—Living on the ground under rotten wood and palm-leaves. Found sporadically over the whole of Sunday Island.

Elasmias inconspicua (Brazier).

Tornatellina inconspicua Brazier, Pro. Zool. Soc., 1872, 619, 1873.

Recorded, Iredale, Pro. Mal. Soc., x, 386, 1913.

Habitat.—In Denham Bay, Sunday Island, living on a patch of kawakawa (Macropiper excelsum). Found during rain crawling on the stems and under-surfaces of the leaves.

Distribution.—Lord Howe Island.

Tornatellina novoseelandica (Pfeiffer).

Tornatellina novoseelandica Pfeiffer, Hel. Viv., iii, 524, 1853.

Recorded, Pfeiffer, 1863 (Iredale, Pro. Mal. Soc., x, 386, 1913).

Habitat.—Living on the trunks of trees and palms, Sunday Island.

Distribution.—New Zealand.

Tornatellina subperforata Suter.

Tornatellina subperforata Suter, Pro. Mal. Soc., viii, 263, 1909.

Recorded, Suter, l.c.

Habitat.—Living on the ground under stones, leaves, and wood, Sunday Island; extremely abundant. This is the species which Iredale (Pro. Mal. Soc., x, 364, and Trans. N.Z. Inst., 47. p. 481, ante) refers to T. novoseelandica.

Distribution.—New Zealand.