DELPHINULA. 269 



D. NiTiDA Verrill and Smith, 1885. PI. fi5, fig. 10. 



Shell t^mall. fragile, very delicate, with a slight .«ilvery iridescence. 

 Our specimen which has lost the apex, consists of o gradually en- 

 larging whorls, entirely disconnected with each other and nearly 

 round in a cross section. When perfect the spire must have been 

 rather elevated, gradually tapering to an acute tip. The surface is 

 sculptured by thin elevated riblets, crossed by distinctly raised re- 

 volving lines of about the same size, producing a pretty regularly 

 cancellated or reticulated sculpture, in which the meshes are mostly 

 elongated in the direction of tlie spire around the periphery, but in 

 the opposite direction on the lateral and inner surfaces ; the trans- 

 verse riblets are m^ist elevated on the uj^per sides of the whorls, 

 where they rise into small thin lamellre ; they also form similar 

 lamellae on the inner and lower surfaces ; the revolving lines are 

 most consijicuous ai'ound the periphery ; minute but distinctly 

 raised lines of growth also cross the intervals between the riblets. 

 In a front view of the base the shell ajipears umbilicated, and the 

 upper whorls can be partially seen within the umbilicus. Color 

 silvery white, slightly iridescent. Alt. (of last three whorls) 5, 

 diam. 4 mill. ; diam. of aperture, 1'6 mill. (Verrill.) 



Off' Chesapeake Bay, in. 1428 /»i6-. 



Animal unknown. The systematic position of this form is un- 

 certain ; but tlie pearly structure of the shell indicates, as Verrill 

 observes, that it belongs in the vicinity of Delphinula. although not 

 I believe, strictly speaking, to tliat genus. 



Subgenus Angahina Bayle, 1878. 



A. LESOURDi B. Wright, 1878. PI. 6S, figs. 6-8. 



Sinistral, profoundly perviously umbilicate, depressed, suborbicu- 

 lar, somewhat solid, transversely cbstate lirate, pale greenish, macu- 

 lated with chestnut ; spire plane, suture profoundly impressed, 

 broadly canaliculate ; whorls remaining 4-2, (the apex wanting,) 

 spirally lirate, the costte about 14 in number; base bearing a series 

 of short spines; umbilical area white within ; aperture round, pearly 

 within, peristome simple, the columellar margin subexpanded. 



Diam. 41, alt. 24 mill. 



Japan. 



Described from a single young specimen, which has every appear- 

 ance of being abnormal. Fischer surmises that the shell is really 



