164 UROCOPTIS, S. G. IDIOSTEMMA. 



lamella, above which there is a spiral callous cord, partially 

 united with the main lamella, in the last four whorls. 



Length 16.5, diam. 4.3 mm.; whorls 14 (Weinl., type). 



Length 17.5, diam. 4 mm. ; whorls 14. 



Length 15.5, diam. 3.8 mm. ; whorls 13. 



Haiti: Gonave Island, in the mountains (Dr. J. J. Brown). 



Cyl. monticola WEINL., Jahrb. d. D. Malak. Ges., vii, 1880, 

 p. 363, pi. 12, f. 17. 



Not closely related to any known species. The strong, 

 spaced riblets, adnate peristome, and the obtuse spiral lamella, 

 reinforced in the last several whorls by a callous cord above, 

 are its chief peculiarities. Figs. 26, 27 were drawn from 

 specimens of the original lot, received from Dr. Brown. 



Subgenus IDIOSTEMMA Pils. & Van., 1898. 



P. & V., Proc. Acad. Nat. Sci. Phila. 1898, pp. 270, 274 

 (July 12, 1898). Type C. uncata Gundl. 



Urocoptis with the axis armed with pairs of hooks or flat 

 nodes, or girt by a wide callous band or double cord bearing 

 oblique nodes or riblets. (Idiostemma, peculiar wreath, i. e., 

 about the axis.) 



Distribution, eastern Cuba. One of the most peculiar and 

 highly evolved groups of the genus, some of the species having 

 the axial armature wonderfully specialized. The radula is 

 also somewhat specialized by reduction of the number of 

 teeth. Vide p. 110. The earliest whorls are smooth in TJ. 

 perlata, delicately costellate in U. lateralis. In other species 

 they are unknown. 



The sculpture in the more highly evolved forms consists 

 of hollow ribs, the acme of sculpture-evolution in the Urocop- 

 tidce. It is noticeable that some species have entered upon 

 the senile stage, this sculpture becoming more or less decadent 

 upon the last whorl or two, the ribs interrupted, irregular, 

 and reduced. Like many other phyla in this family, Idio- 

 stemma is an intensely specialized group, manifested in won- 

 derful and outre forms, but already showing signs of old age. 



There are two series of species; the group of uncata, in 

 which axial hooks are developed, and that of U. geminata, in 



