COCHLOSTYLA OF MINDORO PROVINCE 



463 



a narrow white zone at the summit. The coloration of the shell when 

 the periostracum is removed may be white or it may have a band at the 

 summit, one at the periphery, and a dark area at the umbilicus, or 

 there may be additional spiral zones of various shades of brown or some 

 of those indicated may be absent. The interior of the aperture, even 

 in the dark specimens, and the expanded lip and columella are bluish 

 white. The periostracum as a rule is pale olivaceous-yellow. Nuclear 

 whorls about 2.3, forming a moderately pointed apex, smooth except 

 for incremental lines and on the last portion of the last turn indications 

 of fine spiral striations. The postnuclear whorls are slightly rounded, 

 appressed at the summit, and marked by retractively slanting lines of 

 growth and closely approximated spiral striations, which are present 

 on both spire and base. The suture is slightly impressed, and the 

 periphery is somewhat inflated and shows an indication of an obsolete 

 angle. The shortness causes this to appear inflated and strongly 

 rounded. The aperture is broadly oval, the peristome being very 

 broadly expanded and reflected. That of the inner lip is curled over to 

 form a narrow umbilicus. The parietal wall is covered with a thin 

 callus. 



This species occupies eastern Mindoro from Calapan to Bulalacao. 

 Its small partuloid shape will differentiate it from all the other 

 Prochilus. 



Sixty-one perfect specimens before me yield the following measure- 

 ments: 



