BRACHYPODELLA, S.-G. BREVIPEDELLA. 45 



Subgenus BREVIPEDELLA Pilsbry, nov. 



The shell is clear corneous, moderately stout in figure, trun- 

 cate, and densely, evenly rib-striate, the last whorl somewhat 

 angular below, very shortly free. The apex is delicately cos- 

 tulate vertically (pi. 8, fig. 55) ; the axis simple, slender, and 

 nearly straight. The central tooth of the radula has a nar- 

 row, peg-like cusp ; both laterals have small, peg-like ecto- 

 cones (pi. 9, fig. 1, B. angulifera; fig. 2, B. imitatrix). Type 

 B. imitatrix. 



A Haitian group, with one species in Cuba and one in 

 Porto Rico, distinguished chiefly by the narrow cusp of the 

 central tooth, but with minor features of the sculpture and 

 form of the shell which will enable it to be recognized, though 

 hardly defined intelligibly from shell-characters alone on* 

 account of their similarity in several groups, such as Cochlo- 

 dinella, Bactrocoptis and Simplicervix. The adult shell of 

 the Jamaican section Simplicervix, indeed, is practicably in- 

 distinguishable from that of Brevipedella, but the different 

 apex shows it to belong to another line of differentiation, the 

 resemblance of adult shells being due to convergent evolution. 



The radula of Brevipedella is characteristic by the very 

 small size of the central tooth, which is narrower than in any 

 other of the subordinate groups of Brachypodella. Its cusp 

 is short, upright and peg-like, as are the ectocones of the lat- 

 eral teeth. The teeth are extremely similar in the four species 

 I have examined, B. imitatrix (pi. 9, fig. 2), B. angulifera (pi. 

 9, fig. 1), B. portoricensis, and B. weinlandi. There are five 

 or six marginal teeth on each side. 



In distribution Brevipedella resembles the banded Carac- 

 olus species, and, like them, part of the forms of the three 

 islands are but slightly differentiated. 



I. Suture crenulate, B. weinlandi, no. 1. 

 II. Suture even. 



1. Length 16, diam. 3 mm., whorls 13 to 14. 



B. Jcraussiana, no. 2.. 



2. Length 9 to 11, diam. about 2.5 mm., whorls 8 to 9%. 



a. Haiti, B. imitatrix, no. 3 ; Cuba, B. angulifera,. 

 no. 4. 



