HYPSELOSTOMA. 187 



built upward in a tube of good size, upper side and at the 

 periphery obtusely carinate, deeply guttered above the carina, 

 obtusely angular around the umbilicus. Aperture almost 

 horizontal, looking upward, rounded-tetragonal; peristome 

 simple, thin, expanded throughout. Parietal lamella strong, 

 much elevated, somewhat doubled; one columellar and two 

 palatal lamelliform teeth opposed in form of a cross. Diam. 

 maj. 4, min. 3, alt. 2.1 mm. (Mlldff.). 



Philippines: Coron, in the Calamianes group (C. Roebelen). 

 Also Busuanga. 



Hypselostoma roebeleni MLLDFF., Nachrblatt. d. Malak. 

 Ges., vol. 26, June 1894, p. 100. 



This species differs from H. tiibiferum by the sculpture, 

 absence of a basal keel around the far narrower umbilicus, the 

 want of a basal lamella, and other features. It is not directly 

 related to tubiferum, being a species of the Philippine group 

 which, evolving parallel to tubiferum, has reached the same 

 stage. It has the sculpture, texture and dentition of other 

 Philippine species. 



12. HYPSELOSTOMA EDENTULUM Moellendorff. PL 32, fig. 12. 



Shell perforate, elevated turbinate, thin, subpellucid, lightly 

 striatulate, somewhat decussated by microscopic spiral lines, 

 corneous-brown. Spire rather elevated, the sides straight, 

 apex oblique, rather obtuse. Whorls 5!/4, angularly convex, 

 separated by a very deep suture, the last whorl obtusely an- 

 gular at the periphery, ascending gradually, then becoming 

 shortly free. Aperture vertical, rhombic, the peristome free, 

 thin, narrowly expanded throughout. No teeth. Diam. maj. 

 3.25, alt. 3.25 mm. (Mlldff.). 



Philippines: Sangat Island, Calamianes group (C. Roe- 

 belen). 



Hypselostoma edentulum MLLDFF., Nachrbl. d. M. Ges., vol. 

 26, June 1894, p. 100. 



Well distinguished by the absence of teeth. The initial 

 whorl has minute granules, which on its latter part become 

 arranged in spiral rows, spiral striae appearing on the second 

 whorl. 



