UROCOPT1S. 109 



The central row of the radula consists of teeth decidedly 

 narrower than the others, and having a single, simple cusp. 

 The side teeth are all of the same form fundamentally, as de- 

 scribed above, merely decreasing in size and becoming shorter 

 towards the lateral borders of the lingual band; some of the 

 outer teeth usually distorted, being inclined obliquely inward. 

 The cusps are very broad, blunt and rounded distally, and the 

 sides of the reflected portion usually overhang the peduncle 

 somewhat. The modification of the radula in the subgenera 

 Urocoptis, Cochlodinella, Idiostemma, Maceo and the several 

 sections subordinate to Gongylostoma, is not great. In some 

 forms there are many, in others few teeth in a transverse row, 

 and when few, the teeth diminish rapidly in size, and espe- 

 cially in length, giving the row an irregular appearance. 

 These minor modifications are shown in the figures of plates 

 60 and 61, and are described below. The chief peculiarities 

 of the radula are the wide separation of ectocone from meso- 

 cone, the total absence of any indication of an entocone, even 

 on the outer teeth, the narrowness of the central teeth and the 

 absence of side cusps thereon, and the obliquity of the trans- 

 verse rows. 



Subgenus UROCOPTIS. In all the Jamaican forms the cen- 

 tral tooth is very narrow. Laterals numerous and similar, 

 the formula being 14.1.14 = 29 in U. lata manchionealensis 

 (pi. 60, figs. 1, 2, 3) ; fig. 1 representing a lateral tooth in pro- 

 file. In U. san guinea, Fischer found 12.1.12x115 teeth; in 

 U. ~brevis, 10.1.10 x 103. In the section Bactrocoptis, U. rosea 

 montana (pi. 60, fig. 4) has 13.1.13 teeth, like those of the 

 larger species. 



In U. poeyana (pi. 61, fig. 19), belonging to the subgenus 

 COCHLODINELLA, the radula is very small, with 10.1.1.0 teeth, 

 the middle tooth comparatively wide, its cusp as large as the 

 ectocone of the adjacent lateral. In this respect the radula 

 resembles that of Gongylostoma and Autocoptis, and differs 

 conspicuously from that of Jamaican Urocoptis. 



Subgenus AUTOCOPTIS. The teeth of U. sericea (pi. 50, figs. 

 9, 10) resemble those of CocModinclla and Gongylostoma in 

 the lengthened mesocones, comparatively large ectocones, and 

 wide teeth of the central row. 



