COCHLOSTYLA-CORASIA. 105 



Helicifbrm, depressed thin Cochlostylas, lacking hydro phanous 

 bands, and with the expansion of the lip narrow, compose the section 

 Corasia. They are arboreal in habits. 



Here may be grouped all of the species of Cochlostyla ranging 

 outside of the Philippine Islands ; including the group of H. hunteri, 

 tricolor and their allies, of the Solomon Islands, a portion of which 

 have hitherto been referred erroneously to Geotrochus by Pfeiffer 

 and other authors. 



Like all of the sectional groups which have been established in 

 Cochlostyla, this section is not well differentiated from several others. 

 Through the group of C. regince a connection with the section 

 Chlorcea ( C. dryope, paradoxa, etc.) is established ; and again such 

 species as C. intorta lead toward the section Callicochlias. In a 

 general way, however, Cklorcea differs from Corasia in its deflexed 

 body-whorl, wide lip, and the frequent presence of apical and col- 

 umellar dark spots ; and Callicochlias differs in its more globose 

 form, wider lip and the presence of "hydrophanous" cuticle. 



The species may be thrown into four groups; 



1. Group of C. lactiflua, Solomon Is. 



2. Group of C. extensa, Moluccas and New Guinea. 



3. Group of C. regince, Philippines. 



4. Group of C. virgo, Philippines. 



(1) GROUP OF C. LACTIFLUA. 



Thin shells of glassy texture, light colored, usually translucent- 

 whitish, sometimes varied with brown. Axis perforate or closed ; 

 form varying from globose- turbinate to depressed, the periphery 

 carinated ; apex obtuse ; whorls 3^-5. Surface generally showing 

 spiral striae. Lip reflexed, at least below. Distribution, Solomons 

 and some adjacent islands. 



The shell characters given above define a natural group, the 

 various species of which have heretofore been distributed by authors 

 in Geotrochus and Corasia. 



Mr. C. F. Ancey has proposed as a genus or subgenus the name 

 Crystallopsis for H. hunteri and H. allisteri ; but the characters he 

 assigns do not cover the group as here understood. 



C. HUNTERI Cox. PL 13, figs. 41, 44, 45. 



Umbilicus open, deep, half-surrounded by the broad curved col- 

 umellar lip ; globose-depressed, carinated, thin, whitish-translucent. 



