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Show 320 MR. E. A. SMITH ON THE [Apr. 1, RISSOA (SETIA) TRIANGULARIS, Watson. Rissoa (Setia) triangularis, Watson, ' Challenger' Gasteropoda, p. 611, pi. xlvi. fig. 2. Hab. Ascension Island, 420 fathoms. ALABA TERVARICOSA (C. B. Adams). Rissoa tervaricosa, C. B. Adams, Proc. Bost. Soc. Nat. Hist. 1845, vol. ii. p. 6. Rissoa (?) melanura, C. B. Adams, Contrib. Conch, p. 116. Hab. Ascension Island (Conry); Jamaica (Adams). The single well-preserved specimen from Ascension is a trifle more slender than any of the examples from Jamaica I have seen. It belongs, however, without doubt to this species, having the spiral striae at the base of the whorls, and some opaque white spots in the same place as in Jamaican shells. This specimen has a single varix on the body-whorl, and its apex is not black, but this I do not regard as an essential feature. After carefully studying the descriptions of R. tervaricosa and R. melanura, and examining a series of both, named by C. B. Adams himself, in Cuming's collection, I feel convinced that they constitute but one species. The number and position of varices is very variable, and their total absence occasionally occurs. The texture and striation are similar in all specimens, and all are white and mostly exhibit at the periphery of the body-whorl a series of opaque white dots, not mentioned by Adams, which are also visible around the lower part of the upper volutions. The apex is not constantly black, but is so occasionally, both in varicose and unvariced specimens. MlTRULARIA DILLWYNI (Gray). Patella equestris., Wood (non Linn.), Index Test. pi. xxxvii. Calyptraa dillwynii, Gray, Ann. Philosoph. 1825, vol. ix. p. Woodward, Man. Moll. pi. xi. fig. 11. Mitrularia dillwynii, Fischer, Man. Conch, pi. xi. fig. 11. Calyptraa martiniana, Reeve, Conch. Icon. vol. xi. pi. iv. figs. 13 a-b. Hab. West Indies (Woodward and Brit. Mus.) ; Philippines (Cuming). This species has the surface extremely uneven and wrinkled, and minutely radiately striated. The internal appendage is very large. 1 think it possible Reeve's locality may be an error. According to Hanley (Index Test. p. 183) this is Patella undulata of Bolten. HIPPONYX ANTIQUATUS (Linne). This species occurs also at St. Helena. STROMBUS BUBONIUS, Lamarck. Hab. West Indies, West Africa at Goree and Rufisque, also Cape Verde Islands. The single specimen from Ascension Island is very like that |