42 COCHLOSTYLA-rHENGUS. 



Section XIII. PHENGUS Albers, 1850. 



Phengus ALB., Die Hel. p. 137, for B. opalinus and B. evanes- 

 cens. v. MARTENS, Die Hel. 2d edit, p. 180, type H. opalina 

 Sowb. SEMPER, Reisen im Archipel. Phil. Landmoll. p. 212. 



Thin-shelled, pale green species, distinctly trochoidal in contour, 

 having no hydrophanous cuticle. 



Semper has restricted this section to the two species given below, 

 and in ray opinion correctly. The shells have the texture and 

 color of Eudoxus but differ in being trochiform instead of oval 

 or ovate. 



Anatomically this section forms a connecting link with Canistrum. 

 The globular accessory gland and the dart sac are becoming obsolete 

 in C. opalina, being much reduced in size, the dart sac containing no 

 dart. 



C. OPALINA Sowerby. PI. 8, figs. 50, 51. 



] rnperforate, pyramidal with flattened base and angular periph- 

 ery; thin, somewhat translucent; of a delicate blue-green color, 

 paler above, the suture having a very narrow white border below. 



The spire is high with straight sides; apex obtuse; whorls 6 to 

 6J, narrow, slowly widening. Aperture very oblique; peristome 

 very narrowly expanded, arched forward above. Colurnella rather 

 wide, arcuate, white. 



Alt. 30, diam. 21 mill. 



Alt. 26, diam. 17 mill. 



Province Cagayan, Luzon; Camiguin de Luzon, Philippines. 



Helix opalina SOWB., P. Z. S., 1840, p. 98. PFR. in Conchyl. 

 Cab. p. 291, t. 49, f. 6, 7 ; Monogr. i, p. 231. REEVE, Conch. Icon, 

 t. 23, f. 97. Cochlostyla opalina SEMP., Reisen Landmoll. p. 212, 

 t. 13, f. 8 (anatomy). 



This species is quite distinct in its high trochiform contour. 



C. DUMONTI Pfeiffer. PL 9, fig. 67. 



Imperforate, trochoidal, rather thin ; color a very faint tint of 

 green below becoming white on the spire, having a narrow sutural 

 margin of red-brown or opaque white, and a peripheral dark line, 

 or a narrow groove in its place. 



The contour is much that of Papuina, being flattened beneath, 

 conoidal above, the periphery obtusely subangular. The surface is 

 lightly striated obliquely ; spire conoidal, apex very obtuse. Whorls 



