UROCOPTIS OF JAMAICA. 113 



by a low ridge, sometimes united with the axis. Haiti. Type 

 U. monilifera. 



Subgenus COCHLODINELLA Pils. and Van. 

 Central teeth of the radula wide; laterals rapidly diminish- 

 ing, their number reduced. Shell small, thin, with a slender, 

 simple axis. Western Cuba. Similar to Gongylostoma in 

 dentition, but the axis is a simple style. Type U. poeyana. 



Subgenus ARANGIA Pils. and Van. 



Shell leugthened,camiae below, the axis with a strong me- 

 dian spiral lamella. Eastern Cuba and Gonave Island. Type 

 U. sowerbyana. 



Subgenus IDIOSTEMMA Pils. and Van. 

 Central teeth rather narrow. Shell long, the axis encircled 

 by a low double cord which is obliquely nodose or ribbed, or 

 having the nodes transformed into pairs of hooks. Eastern 

 Cuba. Type U. uncata. 



Subgenus GONGYLOSTOMA Albers. 



Central tooth of the radula rather wide, its cusp about equal 

 to the ectocones of the adjacent laterals. Shell long, the axis 

 encircled by a thin sub-basal lamella, the edge of which is 

 spinosc or serrate, at least in the earlier whorls; frequently 

 with spiral lamella? above the dentate one. Cuba, chiefly in 

 the west. Type U. clegans. 



Two groups formerly subordinated to Urocoptis belong 

 elsewhere; Amphicosmia of Haiti standing with Brachy- 

 podella, while Spirostemma, a Jamaican group, is related to 

 Anoma (Lia} . 



Subgenus UROCOPTIS Beck. 



Jamaican forms with the central tooth of the radula very 

 narrow, and the axis of the shell simple or weakly twisted. 



Section Spirocoptis Pilsbry, 1902. 



Urocoptis with the shell rather large and stout, the internal 

 pillar distinctly twisted or with a single smooth obtuse spiral 

 plait. Type U. san guinea Pfr. Distribution, Jamaica. 



