252 PROCEEDINGS OF THE NATIONAL MUSEUTvI vol. 85 



rounded, smooth. Postniiclear Avliorls also inflated and strongly 

 rounded, marked by numerous, retractively slanting, axial threads, 

 which increase in strength with the whorls and form slender nodules 

 where they join the much stronger spiral cords. The latter are of 

 less than half the width of the spaces that separate them. Suture 

 well constricted with white tufts of axial ribs crenulating them. 

 Periphery and base inflated, strongly rounded; sculptured like tlie 

 spire. Base openly umbilicated. Last whorl solute for one-tenth 

 of a turn. Aperture broadly ovate ; peristome double, the outer more 

 broadly expanded on the inner lip than on the outer; inner peristome 

 slightly expanded and reflected, adnate to the outer. There is no 

 breathing pore. Operculum thin, corneus, with excentric nucleus 

 covered on the inner half by a coarsely granular calcareous deposit. 

 The type, U.S.N.M. no. 367904, was collected by Dr. Bermudez on 

 palms at the Cueva del Catre, Sierra del Paso Real de Guane. It 

 has 5.2 whorls remaining and measures : Length, 17.0 mm ; greater 

 diameter, 7.4 mm ; lesser diameter, 6.3 nnn. 



Genus CHONDROTHYRA Henderson and Bartsch 



1920. Chotidrothym Henderson ami Bartsch, Proc. U. S. Nat. Mus., vol. ~>S. p. 63. 



Shell varying from ovate-conic to elongate-conic ; m.arked by axial 

 and spiral threads. Peristome broadly expanded in one plane; that 

 is, not notched or inbent at the umbilicus. The breathing pore perfo- 

 rates the parietal wall a little behind the peristome and a little ante- 

 rior to the posterior angle of the aperture. Operculum typically 

 chondropomoid. 



Type: Cyclostoma egreghnn (Gundlach) Pfeiifer. 



KEY TO THE SUBGENERA OF GENUS CHONDROTHYRA 



Outer peristome of inner lip without fold or pit. 



Last whorl decidedly solute and descending Hendersonoma 



Last whorl not decidedly solute or descending Chondrothyra 



Outer peristome of inner lip with fold or pit. 



Outer peristome of inner lip with a fold Plicathyra 



Outer peristome of inner lip with a pit Foveothyra 



Hendersonoma, new subgenus 



ChoTidrothyra of gigantic size, Avith the last whorl decidedly solute 

 for a tenth of a turn and descending. Peristome double, the outer 

 thick, moderately expanded and reflected, much narrower on the 

 parietal wall than on the rest of the aperture, somewhat channeled at 

 the posterior 'angle. Inner peristome thick, narrowly expanded, 

 reflected, and adnate to the outer. 



The large size, solute and descending last whorl, and the fact 

 that the outer peristome of the parietal wall is decidedly free from 



