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Show 1890.] MARINE MOLLUSCA OF ST. HELENA. 261 circa medium ; anfr. ultimus inferne contractus, subrimatus, lirispr&cipuis 6-7, aliisque tenuibus, intercalentibus, cinctus apertura parva, albida vel lilacea, cum canali longit. totius dimidium superans; columella callo tenui, superne tuberculo parvo munito induta; canalis obliquus, angustus, recurvus; labrum intus incrassatum, liris 6-7 instructum. Longit. 14 millim., diam. max. 8. This species has much of the character of two species-the one Can. nodulosus from the West Indies, and the other C. lugubris from Panama, both described by C. B. Adams. The spire of the latter species seems to be rather longer than that of the present species; its aperture is consequently proportionally shorter, and the coloration is not the same. C. nodulosus, which is very closely allied to the present form, besides being differently coloured, is a somewhat more robust species and has a shorter canal, and the whorls seem to be rather less angular. These three forms are difficult to locate generically ; and although I have considered them as belonging to the Tritonidea section of Cantharus, they might with equal propriety be associated with Sistrum. CANTHARUS (TRITONIDEA) L_EVIS. (Plate XXI. fig. 11.) Testa ftsiformi-ovata, alba, lineis transversis saturate fuscis ornata, interque costas fusco tincta; anfr. 10, apicales tres convexi, Iceves, flavescentes, sequentes superne concavi, in medio angulati, infra angulum convexiusculi, costis crassis 9, ad angulum acutis, instructi ; anfr. ultimus elongatus, prope medium contractus, inferne subrimatus; apertura alba, cum canali longit. totius j superans; labrum extus valde incrassatum, intus denticulis ad 6 munitum; columella callo albo, tenui induta ; canalis elongatus, obliquus, recurvus. Longit. 23 millim., diam. max. lOy apertura cum canali 12 longa, 4\ lata. This pretty species recalls certain forms of the genus Siphonalia. It is unlike most species of Cantharus in having no tubercular sculpture, on which account I have called it C. Icevis. COLUMBELLA (ANACHIS) DECIPIENS (C. B. Adams). Buccinum concinnum, C. B. Adams, Proc. Bost. Soc. Nat. Hist. 1845. Columbella decipiens, C. B. Adams, Contrib. Conch, p. 55 ; Reeve, Conch. Icon. pi. xx. fig. 111. Col. crassilabris, Reeve, 1. c. pi. xxviii. fig. 177 a-b. Hab. Jamaica (C. B. Adams). In the Museum are tbe type of C. crassilabris and the specimen of C. decipiens figured by Reeve. They unquestionably belong to the same species. The figure of the former is not good as regards form, and is very greatly enlarged, although no indication of this appears on the plate. The only specimen from St. Helena forms part of a collection made by Mr. J. Macgillivray many years ago. |
