COCHLOSTYLA OF MINDORO PROVINCE 399 



Subgenus Halocochlea Bartsch 



1932. Halocochlea Bartsch, Journ. Washington Acad. Sci., vol. 22, p. 336. 



In this subgenus the shell is helicoid. The periphery is angulated. 

 The last whorl slopes almost at the same angle posteriorly and basally 

 from the periphery. The outer lip is slightly expanded and reflected, 

 and the columella is very oblique and excavated. There is scarcely 

 any calcareous material in the shell, which is thin and diaphanous. 



Type: Cochlostyla (Halocochlea) lillianae Bartsch. 



COCHLOSTYLA (HALOCOCHLEA) LILLIANAE Bartsch 



Plate 97, Figures 4-6 



1932. Cochlostyla (Halocochlea) lillianae Bartsch, Journ. Washington Acad. Sci., 

 vol. 22, p. 336. 



The shell is exceedingly thin, in fact so thin that by transmitted 

 light one is able to see all the internal structure, including the col- 

 umella, as plainly as if one were looking through a piece of thin greenish 

 glass. The nuclear whorls are white, and the postnuclear whorls very 

 pale yellowish olive-green. There is a dark chestnut-brown columellar 

 area, which contrasts markedly with the green base and the white of 

 the columellar area. The reflected outer lip is pale green, while the 

 interior of the aperture is pearly gray. There is also a very slender 

 brown thread separated by a space about as wide as a thread from the 

 summit of the turn on the last whorl. Nuclear whorls 2, well rounded, 

 smooth. The postnuclear whorls are somewhat inflated, strongly 

 rounded, marked by fine incremental lines, which have an almost 

 threadlike appearance, and numerous, closely spaced, microscopic 

 spiral striations on both spire and base. The aperture is almost 

 circular; the suture is slightly impressed and the periphery obsoletely 

 angulated. The base is moderately long and strongly rounded. 



The type (U.S.N.M. no. 255825), collected by Col. Edgar A. 

 Mearns on Mount Halcon, has 4.2 whorls and measures: Length,, 

 27.7 mm; greater diameter, 28.3 mm; lesser diameter, 23.7 mm. 



I have taken great pleasure in naming this species for Miss Lillian 

 Mearns, daughter of the collector. It is one of the most exquisite 

 species known from the Philippine Islands, and the type at the present 

 time constitutes the only known specimen. 



Subgenus Helicostyla Ferussac 



In this subgenus the shell varies from ovate to elongate-ovate. The 

 apex is blunt and the base expanded and usually conspicuously differ-, 

 entiated from the spire by color markings. A thin dehiscent perios-- 

 tracum is present. The outer lip is somewhat expanded and reflected, 

 and the columella slightly excavated. 



