CUBAN SUBFAMILY CHONDROPOMINAE TORRE AND BARTSCH 383 



fine, low, rounded nodules at their intersection. The axial riblets are 

 slightly closer spaced than the spiral threads. Of the spiral threads, 

 16 occur between the periphery and the summit on the last turn. 

 Periphery well rounded; base moderately long, strongly rounded 

 and marked by the continuation of the axial riblets which extend into 

 the umbilicus, and 14 spiral threads of about the same strength as 

 those on the spire. The umbilicus is rather wide, and in addition to 

 the axial riblets shows strong spiral threads. Aperture ovate; per- 

 istome double, white, the outer narrowly expanded, forming a con- 

 spicuous pointed auricle at the posterior angle, the inner also ex- 

 panded and appressed to and adnate to the outer, conspicuously sepa- 

 rated only at the auricle. Operculum thin, paucispiral, corneous. 



The type, U.S.N.M. no. 493291, was collected by Jolin B. Hender- 

 son at Santa Lucia, La Silla, Oriente. It has 4.4 whorls remaining 

 and measures: Length, 15.3 mm; greater diameter, 9.0 mm; lesser 

 diameter, 7.4 mm. 



This species can readily be distinguished from the other members 

 of Chondropoma {Chondropo^nisca) by its much more elongated 

 form. 



Subgenus Chondropomartes Henderson and Bartsch 



1921. Chondropomartes Henderson and Bartsch, Proc. U. S. Nat. Mus., vol. 

 58, p. 60. 



Shell ovate-conic, the intersections of the axial ribs and spiral 

 threads forming sharp cusps. Operculum with a very heavy callus. 



This group, as set up by Henderson and Bartsch, was a hetero- 

 geneous assemblage. Additional material collected about Matanzas 

 shows that C. (C.) presasiamim, the type species, is connected with in- 

 tergradient forms with C. (C.) irradians. IVliile the hollow spines 

 formed by the intersection of the axial ribs and spiral sculpture 

 may be reduced to almost the vanishing point, they are, nevertheless, 

 indicated in all the forms. 



The present arrangement was made possible and easily intelligible 

 by the accessions obtained by Dr. de la Torre and from his coworkers, 

 which show that the subgenera as now conceived constitute a per- 

 fectly natural group. An interesting character is the very heavy 

 callus on the operculum. The group, as now constituted, centers 

 about Matanzas. 



Type: Chondropoma presasianum (Gundlach) Pfeiffer. 



KEY TO THE SPECIES OF SUBGENUS CHONDROPOMARTES 



Spines very strong presasianum 



Spines very fine irradians 



Spines intermediate between the above portuandoi 



