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Show 58 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Jan. 20, I am now inclined to separate Triforis from Cerithium by reason of the differences in the apex or embryonic part of the shell and in the former having a short basal canal instead of a mere groove or notch. The spire of Triforis is finely pointed, in Cerithium it is blunt. In Triforis the apical whorls are much narrower in proportion, and are closely striated lengthwise. In Triforis the canal is small and nearly if not quite closed, as in Murex ; in Cerithium the groove or notch is comparatively large and quite open. According to Meyer and Mbbius there is also a characteristic distinction between the animals and odontophores of the two genera. The snout or proboscis in Triforis and Cerithiopsis is retractile, while in Cerithium it is contractile. The radula of T. perversa contains about 26 transverse and short denticulated plates. Triforis appears to be congeneric with Cerithiopsis, and to belong to the same family. When the shells of T. perversa and C. tubercularis are exhibited one before a mirror and the other not, it will he seen that almost the only differential character consists in the lower or basal portion of the mouth being more closed in the Triforis than in the Cerithiopsis. Seguenza and Monterosato regard T. perversa and T. adversa as distinct species because the former is larger than the latter. I cannot agree to their separation on those grounds, and I am not aware of any other difference. Size seldom if ever constitutes by itself a specific character. Professor Stossich kindly gave me a specimen which is more than an inch long besides the apical whorls, which had disappeared, and another specimen which, although quite perfect, was scarcely a line or the tenth part of an inch in length ; both specimens were from the Adriatic. Besides Murex adversus of Montagu there are many other synonyms. Cerithium nigrocinctum of C. B. Adams, from the North-Atlantic coasts of the United States, is closely allied to the present species, if it be not the same or one a variety of the other. 2. TRIFORIS ASPERA1, Jeffreys. (Tlate VI. figs. 7, 7a.) S H E L L elongated, rather solid, nearly opaque and glossy: sculpture, rows or bands of small tubercles (18-20 on the last or bottom row), which arise from the mutual intercrossing of longitudinal and spiral striae; of these rows there are usually three on the last whorl above the periphery, and the same number on several of the succeeding whorls and afterwards two only ; each of the apical whorls (3 or 4) is closely striated lengthwise and encircled by two spiral lines; the periphery is defined by a rather strong ridge, a little below which is another ridge, besides a shorter and smaller one at the base ; the tubercles which compose the lower two rows are larger and more prominent than those of the uppermost or third row: colour pale yellowish, with a faint tinge of brown ; apical whorls dark brown: spire tapering to a fine point ; apex pinched-in and narrower than the rest of the spire: whorls 21-22, compressed, gradually enlarging; the last equals only from ^ to ^ of the shell: suture slight, indicated by (he 1 Rough, |