269 



* * * 

 D. NITIDA Yerrill and Smith, 188,"). PI. 65, fig. 10. 



Shell small, fragile, very delicate, with a slight silwry 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 spirt' 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 si/e, producing a pretty regularly 

 cancellated or reticulated sculpture, in which the meshes are mostly 

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

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

 verse riblets are most elevated on the upper sides of the whorls, 

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

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

 most conspicuous around 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 appears umbiiicated, 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, 1M> mill. ( JV>v///. > 



Off Chesapeake Buy* in, 142o/wx. 



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

 certain ; but the pearly structure of the shell indicates, a.-- Yerril] 

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

 I believe, strictly speaking, to that genus. 



Snbgenus AN<;AKINA Bayle, 1878. 



A. LESOURDI H. Wright, 1878. PI. 68, figs. 6-8. 



Sinistral, profoundly perviously umbilicatc, depressed, suborbicu- 

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

 lated with chestnut; spire plane, suture profoundly impressed, 

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

 spirally lirate, the costa? 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. L>4 mill. 



Japan. 



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

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



