MUSEUM OF COMPARATIVE ZOOLOGY. 391 



II;il)itat. Station 134, near Santa Cruz, in 248 fnis., sand, living, bottom 

 temperature 54°. 5 F. Station 22, off Baliia Honda, Cuba, in 220 inis., bottom 

 temperature G2°.0. Stations 206 and 300, Barbados, in 82-84 fms., bottom tem- 

 perature 00° to (;i°.r). Barbados, 100 fms. Sand Key, in 80 fms. U. S. Fish 

 Commission Stations 2595 aud2610, off the coast of North Carolina, in 22-63 fms., 

 gravel. 



The variety: Station 30, off Cuba, in 84 fms., bottom temperature 60°.(). 

 Off Sombrero, in 54 fms. Off Havana, Sigsl)ee, in 80 fms. Station 273, Bar- 

 bados, in 103 fms., bottom temperature 59°. 5. Station 247, off Grenada, in 

 170 fms., gray ooze, bottom temperature 53°. 5 F. 



The spiral sculpture in this species may be, and generally is, either nodu- 

 lous, or marked with strong imbrications which sometimes become spines. In 

 some specimens and especially in young ones we may have the imbrications 

 absent and the shell marked with flexuous radii, which sculpture the interspaces, 

 but not, or only slightly, the carinjB. In other specimens the fine spirals are 

 absent from the base, which is then marked with ilexuous raised radii, or by 

 irregularly elevated, radiating, not very prominent granulations. The young 

 shells are proportionally less elevated, and have a larger umbilicus. No trace 

 of color has been observed on any of the specimens examined. 



Subgenus LIPPISTES Montfort. 

 Lippistes acrilla n. s. 



Plate XXXII. .Figs. 6, 11. 



Shell thin, white, planorboid, of three and a half whorls; radiating sculpture 

 of about fifteen ridges, faint on the base and summit, making small nodules 

 where they cross the fine spirals, and prominent and strong on the periphery 

 between the three peripheral carinae. Other radiations are only due to lines of 

 growth which are sometimes slightly elevated. Spiral sculpture of three 

 prominent and strong peripheral ridges, of which the uppermost forms the chief 

 periphery, the others being slightly nearer the axis; between these, nearly 

 square deep reticulations are formed by the radiating ridges before described. 

 Beside these there are three faint spirals on the upper and three on the basal 

 surface, nodulated at their intersections with the radii. Umbilicus ample; 

 inner margin of the aperture nearly circular, the outer part modified by the 

 sculpture. Max. diam., 4.3; min. diam., 3.0; alt., 2.0 mm. 



Habitat. Garden Key,Tortugas, Florida, among small beach shells sent by 

 a correspondent to the U, S. National Museum. 



The specimen looks as if not quite adult. It differs from X. formosissima 

 Brugnone, of the Mediterranean, in having three strong peripheral costge in- 

 stead of one, and three above and below instead of one in each situation. 



