ODOSTOMIA. 329 



Shell elevated, pointed, smooth, and glossy, of an ivory-white 

 color ; Avhorls about eight, flat, separated by a sharp, slightly de- 

 pressed suture, on which are from three to five revolving 



Fif". 598. 



lines, of which the two next below, and the one immediately 

 above the suture are most deeply sculptured ; about the front 

 of the lower whorl are usually ten or twelve very fine lines 

 also ; aperture narrow, about one third the length of the 

 shell, acutely angular above ; outer lip sharp and thin, some- ^" "g-^''"' 

 times showing Avithin, and on its sharp edge, the impressed 

 lines ; the inner margin regularly curved ; the pillar, widening and 

 expanding a little, is produced so that an acute angle is formed by 

 the junction of the two lips in front ; about the middle of the inner 

 margin is a single, sharp, oblique fold, formed by the revolution of 

 the outer lip within the shell ; operculum horny ; apex nearly ter- 

 minal, sub-spiral. Length, one fourth of an inch; breadth, one 

 tenth of an inch ; divergence, twenty-three degrees. 



First found by Colonel Totten on the shores of Rhode Island, 

 adhering to Pecten irradiatis. Since then it has been found by 

 Professor Adams among sand from New Bedford Harbor. 



Lynn tiarbor (^Haskell) ; Buzzard's Bay to New York (^Stimpson). 



Odostomia ssminuda. 



Fig. 178. 



Shell acute-conic, white, with coarse revolving lines, crossed on the upper 

 whorls, and on the upper half of the lower whorl, by longitudinal lines. 



Jamiuia scminuda, Ada3IS, Bost. Joiirn. Nat. Hist. ii. 280, pi. 4, fig. 13. 

 Odostomia semlnuda, Gould, Inv. 1st cd. 273, fig. 178. — De Kay, N. Y. Moll. 115, pi. 8, 

 fig. 175. — Stimpsox, Check Lists, 5. 



Shell acute-conic, glossy white, translucent ; whorls six or seven, 

 convex, the upper ones and one half the lower wdiorl w^tli numer- 

 ous ridges or folds, crossed by three equidistant revolving 

 lines, giving the surface a granulated appearance ; at the ^'°' ° 

 base of the lower whorl are four more revolving lines, be- 

 ginning on the middle, where the folds terminate aln'uptly ; 

 suture distinct, divided by an indistinct spiral ridge ; aper- 

 ture oval, one third the length of the shell; the outer lip o.se7m- 



■1. -, n 111 1 • ^• • nulla. 



very thin, and scalloped by the revolving lines ; the base is .3 



prolonged into a concave angle, and rising, revolves Avithin 



the shell, forming a single inconspicuous fold on the pillar. Length, 



