HEMITROCHUS. 241 



H. streatori belongs evidently to the section Hemitrochus; and 

 like the other species of that division the axis is perforated in young 

 shells. There is a general resemblance in form and color-pattern to 

 H. amplecta but that shell and its allies are umbilicate. Its affinity 

 is greatest with H. caymanensis, and with Tryon's H. guassoini, 

 described from the tiny islet of Navassa, but the slreatori is more 

 depressed than guassoini, with more oblique aperture, fewer more 

 rapidly enlarging whorls, etc. H. streatori differs from caymanensis 

 in the dark apex and lip, and the continuous supraperipheral band, 

 etc. These shells, guassoini, streatori and caymanensis should be 

 inserted in my monograph of Hemitrochus in the Manual of Con- 

 chology immediately following the group of amplecta, rufoapicata and 

 graminicola (p. 37). It may be noted that with the exception of the 

 last-named form, these three are the only species of Hemitrochus 

 ranging south of Cuba. 



H. CAYMANENSIS Maynard, n. sp. PL 56, figs. 10, 11, 12. 



Shell imperforate, depressed, with low-conoidal spire. Surface 

 shining, sculptured with fine growth-lines, which generally show a 

 tendency to form spaced costulse; pale buff-white, h a vingfour spiral 

 bands composed of oblique rhombic spots, two bands above, one at the 

 periphery and one broader band on the base. 



The spire is low but conoidal, apex obtuse, whitish or light brown ; 

 whorls 4J-4I , convex, the last rounded at the periphery, rather flat- 

 tened beneath, rather deeply and suddenly deflexed in front. 



Aperture quite oblique, truncate-oval, white and showing the 

 bands within ; peristome very little expanded, acute, spotted by the 

 terminations of the bands ; strengthened by a narrow rib or lip 

 within ; columellar margin sloping, nearly straight, closely reflexed 

 and adnate at the axis ; termination of the peristome remote. 



Alt. 8|, greater diam. 12, lesser 11 mill. 



Alt. 8?, greater diam. 11, lesser 9J mill. 



Little Cayman Island. 



This species is closely allied to H. streatori Pils., and may prove to 

 be a variety of that species ; but it differs in the less reflexed basal 

 lip, the light-colored apex and peristome, and the spotted bands. 



H. MAYNARDI Pilsbry. PL 56, figs. 13, 14, 15. 



Shell nearly-covered umbilicate, depressed, rather thin. Spire 

 slightly convex, apex obtuse. Surface sculptured with prominent 

 thread-like striae in the direction of growth lines ; pale fleshy brown, 

 16 



