394 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvi. 



CHIONE (CHIONE) AMATHUSIA Philippi, 1844. 



Gulf of California to Panama, in 7 to 24 fathoms. 



Perfectly distinct from C. gnidia, with which it has been confused, 

 Venus encausta is said b^^ Sowerby to be a synonym, but no author is 

 cited for it in the Thesaurus. It is smaller, more pyriform. and with 

 much less prominent lamellation and finer radial sculpture. 



CHIONE (CHIONE) GNIDIA Broderip and Sowerby, 1829. 



Cerros Island, on the Pacific shore of Lower California, the Gulf of 

 California, and south to Panama Bay, in 7 to 24 fathoms. 



This is the largest and finest of the genus, reaching a length of 

 85 mm. It is white inside and, when fully adult, has the crenulated 

 inner margin of the valves brown. I suspect V. ornatissima Broderip, 

 1835, to be founded on a particularl}^ oval and lamellose young shell of 

 this .species. 



CHIONE (CHIONE) EFFEMINATA Stearns, 1890. 



"Panama Bay;"' Thomas Bridges. 



A small, compressed, closely I'eticulate species, gra>'ish white exter- 

 nally, wholly purple internally, with the hinge and profile of an 

 A^iomalocardia., to which group I am tempted to refer it, though it, 

 in some respects, seems closer to Cldone. It has a verj^ Indo-Pacific 

 aspect. 



CHIONE (CHIONE) DARWINI Dunker, 1857. 



Mazatlan to Panama (Romer). 



Regarded as a vai"iety of C. gnld'ia bv Carpenter, 1857, and as a 

 variety of C. amathusla by Deshayes, 1858. It is stated to differ b}' 

 having the ventral faces of the concentric lamellae polished purple 

 brown, as well as the lunule and escutcheon. I have seen no speci- 

 mens which agree with the descriptions, and regard it as a doubtfully 

 distinct form and perhaps a variety of C. suhrostrata. It was 

 described from Dunker's manuscript bv Romer. 1857. 



CHIONE (LIROPHORA) OBLITERATA Ball, 1902. 



Humboldt Bay, Gulf of Panama; Arthur Schotl. 



This is the analogue of C. latUlratd Conrad of the Atlantic fauna, 

 from which it differs in having the concentric ri])s less elevated and 

 more irregular and tlie shell more rostrate. The coloration is about 

 the same. 



CHIONE (LIROPHORA) KELLETTII Hinds, 1844. 



Gulf of California and south to the Bay of Panama in S to 50 

 fathoms. 



A remarkable species, in which the concentric ri])s (of a yellow- 

 brown color) are smoothly coalescent on the disk, l)ut are expanded as 



