320 MR. E. A. SMITH ON THE [Apr. 1, 



RissoA (Setia) triangularis, Watson. 



Hissoa (^Setia) triangularis, Watson, ' Challenger ' Gasteropoda, 

 p. 61 1, pi. xlvi. fig. 2. 



Hab. Ascension Island, 420 fathoms. 



Alaba tervaricosa (C. B. Adams). 



Eissoa 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 {Gonry); 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 })lace as in Jamaican shells. This specimen lias 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 

 S. 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. 



MiTRULARiA DiLLWYNi (Gray). 



Patella equestris. Wood {nan Linn.), Index Test. pi. xxxvii. fig. 1. 



Calyptrcea dillwynii, Gray, Ann. Philosoph. 1825, vol. ix. p. 407 ; 

 Woodward, Man. Moll. pi. xi. fig. 11. 



Mitrularia dillwynii, Fischer, Man. Conch, pi. xi. fig. 11. 



Calyptrcea mai-tiniana. Reeve, Conch. Icon. vol. xi. pi. iv. 

 figs. 13 a-b. 



Hab. West Indies [Woodioard and Brit. Mus.) ; Philippines 

 {Cuming). 



This species has the surface extremely uneven and wrinkled, and 

 minutely radiately striated. The internal appendage is very large. 

 I 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 (Linue). 

 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 



