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The Atoll of Funafuti, Ellice group : its zoology, botany, ethnology and general structure based on collections made by Charles Hedley of the Australian Museum, Sydney, N.S.W.

Cerithium breve, var. Ellicensis, var. nov. — (Fig. 20)

Cerithium breve, var. Ellicensis, var. nov.
(Fig. 20).

Shell conical, blunt in front and tapering somewhat rapidly behind. Colour cream. Apex of the only example broken, remaining whorls seven, of which the upper are much eroded. Sculptured by low rounded longitudinal ribs which crenulate the suture and project at the periphery, on the antipenultimate there are thirteen of these, on the penultimate fifteen, and on the last whorl where they tend to disappear, there are counting varices, eleven. The last whorl is girdled by six, the earlier by two zones of raised and polished callus, which swell into greater prominence on the crest of each rib. The space between these zones is scored by sharp, narrow, revolving grooves, widest apart in the centre. Behind the aperture is a broad outstanding varix which ascends the penultimate whorl to the lower callus zone. Half a whorl further back is another but much weaker varix. No varices can certainly be distinguished on the spire, though some slightly more prominent ribs there suggest them. Aperture perpendicular, oval, anterior canal short, oblique and deeply cut; inner lip with a heavy layer of callus terminating above and below in a ridge tubercle. Anteriorly and externally the columella is reflected, not appressed to the shell. Outer lip within much thickened, armed with seven entering ridges of callus. Length 10, breadth 5 mm.

Fig. 20.

Fig. 20.

One specimen from the lagoon beach, differs from type by smaller size and less prominent sculpture.

Of the figures accessible to me, this form most resembles those of C. hanleyi, Sowerby, and C. rubrolineatum,, Sowerby,* from which it seems to differ by smaller size, absence of coloured bands, and apparently different arrangement of the teeth of the aperture. Tryon unites these two, and comments severely on this author's nomenclature. Sowerby himself, by a negligence truly remarkable, omits both from his later Monograph in the Conchologia Iconica. The original figure of C. breve seems to be badly drawn. As Kiener had access to the original specimens of Quoy and Gaimard, I would rather base an identification on his different but well drawn figure, Smith has suggested§ that "C. breve may be page 433only a form of G. morus, Lamk." Tryon, ever ready to reduce synonymy, agreed in this view. Whatever may be deemed the value of C. breve, it cannot be adjudged an absolute synonym of C. morus. The type of C. breve came from Tongatabu. The shell does not seem to have been again observed.

* Sowerby—Thesaurus Conch, ii., 1855, pl. clxxxiii., figs. 193 and 199.

Voy. "Astrolable" 5 Zool., 1835, pl. liv., fig. 9.

Kiener—Loe. cit., pl. xiv., fig. 2.

§ Smith—Mollusca, Zool. Coll. "Alert" 1884, p. 65.