474 BULLETIN" 10 0, UNITED STATES NATIONAL MUSEUM 



crinkled. The last whorl is also marked by closely spaced, incised, 

 spiral striations. The postnuclear whorls are appressed at the summit, 

 moderately rounded, marked by retractively slanting lines of growth 

 and closely spaced, microscopic, spiral striations and still finer criss- 

 cross sculpture, which cuts the lines of growth obliquely and is present 

 on both spire and base. Suture slightly constricted. The periphery 

 is feebly obsoletely angulated. The base is rather long, well rounded. 

 Aperture oval. The peristome is strongly expanded and reflected; 

 columella broadly expanded at its insertion and reflected to form the 

 umbilical chink. The parietal wall is covered by a rather thick callus. 



The type (U.S.N.M. no. 313644), collected by Pedro de Mesa at 

 Calawagan, Paluan, Mindoro, has 7.1 whorls and measures: Length, 

 63.8 mm; greater diameter, 29 mm; lesser diameter, 24 mm. 



U.S.N.M. no. 313645 contains eight topotypes received from the 

 same source, seven of which yield the following measurements: 



1 Average. 



J Greatest. 



• Least. 



This race is remarkable for the extreme thinness of its shell and for 

 the enormous variation in size in the different specimens, as brought 

 out by the table of measurements. 



COCHLOSTYLA (CHRYSALLIS) CHRYSALIDIFORMIS ENODOSA Bartsch 



Plate 108, Figure 3 



1932. Cochlostyla (Chrysallis) chrysalidiformis enodosa Bartsch, Journ. Washing- 

 ton Acad. Sci., vol. 22, p. 339. 

 Shell ovate, apparently in perfect specimens covered by a golden- 

 yellow periostracum ; at least this is indicated by a few slireds that 

 are left on our shells and also by the part covered by the parietal 

 callus. The only specimen before me is badly denuded. The peri- 

 stome and aperture are white. The nuclear whorls are well rounded, 

 smooth. The postnuclear whorls are moderately rounded and 

 appressed at the summit, separated by a slightly constricted suture. 



