82 BRACHYPODELLA, S. STR. 



and Lamarck was not that figured by Lister, but a larger 

 shell, with the last whorl free. 



Under these circumstances, I regard the use of the name 

 collaris for any species as inadmissible. It cannot fairly be 

 used for B. cost at a, because the figure in Lister is not good 

 enough for reasonably certain identification, and it is known 

 that that form was not the one intended. It cannot be used 

 for antiperversa, because the first use of the name collaris 

 was in connection with Porto Rican and Barbados forms. 



Group of B. pallida: Haiti, Porto Rico, Virgin Islands, and 



St. Croix. 



Slender shells, cylindric below, tapering above, with car- 

 inate base, straight or almost straight axis, and costulate 

 early whorls. 



The nuclear whorls are costulate, as in continental species, 

 but the first one is somewhat elevated, as in the Caribbean 

 group. The dentition (pi. 10, fig. 17, B. pallida) is similar to 

 that of the other species of the subgenus. 



The spire is quite attenuate when entire. The first third of 

 a whorl is smooth, as usual in Urocoptidce; the next 2% 

 whorls are vertically costulate; then the adult sculpture be- 

 gins, the oblique ribs quite weak at first, merely indicated, 

 but attaining a moderate size by the end of 5% or 6 whorls, 

 where the plug is located, marking the portion ordinarily cast 

 off by adults (Vol. XV, pi. 64, fig. 18, B. chordata). 



Key to Species. 



I. Sculpture of wide-spaced riblets, sometimes interrupted; 

 neck rather long. 



1. Small, 5.7-7.6 mm. long, with 8 to 9% whorls in 

 truncate, 12 to 13 in entire specimens. Santo Do- 

 mingo. B. dominicensis, no. 36. 



2. Larger, 7.6 mm. long or more ; 15-19 whorls in entire 

 shells. 



a. Riblets slender, continuous, usually a little en- 

 larged at the ends; intervals substriate. 



