COCHLOSTYLA OF MINDORO PROVINCE 



469 



summit, slightly rounded, marked by retractively curved axial lines 

 of growth and wavy, moderately deeply incised, rather distantly 

 spaced spiral lines. Suture very slightly constricted; periphery 

 strongly rounded. Base protracted, moderately rounded. Aperture 

 broadly oval; outer lip very broadly expanded and reflected, thick. 

 The inner lip also broadly expanded and very thick and reflected over 

 the umbilical area, leaving only a narrow chink anteriorly. The 

 parietal wall is covered by a thick whitish callus. 



The type (U.S.N.M. no. 313598), collected by Pedro de Mesa 

 at Mangarin or Cagurai, in southwestern Mindoro, has 6.4 whorls 

 and measures: Length, 38.3 mm; greater diameter, 15.9 mm. 



Three additional specimens (U.S.N.M. no. 313599), considerably 

 smaller than the type, yield the following measurements: 



This race is easily distinguished from the other Mindoro shells by 

 its broad white band at the summit. 



Subgenus Chrysallis Albers 



In this subgenus the shell varies from ovate to ovate-conic to 

 pupiform. Its base is slightly perforated. There is a great diversity 

 in the thickness of the shell in the various species and races. The 

 color varies from white through yellow, tawny to brown, and almost 

 blackish brown, and the hydrophanous periostracum is equally vari- 

 able, usually forming axial streaks or figurations of varying width 

 and extent. The aperture may be white or dark within. The peri- 

 stome varies also from white through buff through brown to iridescent 

 bluish black. 



The type is Cochlostyla chrysalidiformis (Sowerby). 



COCHLOSTYLA (CHRYSALLIS) CHRYSALIDIFORMIS (Sowerby) 



Shell elongate-conic to pupiform, ranging in color from almost white 

 through pale straw-color to lemon-yellow. Some races are unicolor, 

 that is, almost white throughout, but even these show near the summit 

 a series of hydrophanous marks corresponding more or less to hydroph- 

 anous axial bands. In shells that have a brown spiral zone im- 

 mediately below the summit, the hydrophanous bands when present 

 in the periostracum cause this brown band to be broken up into spots. 

 The peristome may be white, yellowish, or brownish purple. Usually 



