HYPSELOSTOMA. 181 



tive; like this species, the new one stands perhaps on the 

 border between Boysidia and Hypselostoma, which are fur- 

 ther linked together by forms like B. boettgeri of Java and 

 strophostoma from the West River above Canton. The last 

 whorl becoming free, and its angulation, though quite weak- 

 ened, influence the reference to Hypselostoma (Mlldff.). 



30, H. a. altius n. subsp. PL 31, figs. 11, 12, 13. 



The specimens before me differ somewhat from von Mollen- 

 dorff 's diagnosis, and probably constitute a race or subspecies. 

 The base is barely perforate, much more narrowly than in 

 Boysidia hunana. 



The shell is larger and especially higher and narrower than 

 H. annamiticum. Chestnut-brown, very densely sculptured 

 with filiform, minutely crinkled and often interrupted spiral 

 striae. Whorls 51/2, convex, not angular, the last straightened 

 and built forward, very indistinctly subangular above and at 

 the periphery, rounded beneath. Angulo-parietal lamella bi- 

 lobed. The columellar lamella is bent downward, but enters 

 horizontally. The upper palatal plica descends somewhat. 

 Lower palatal has the broad summit deflected upward. The 

 lip is strongly thickened within. 



Alt. 4.25, greatest diameter including lip 3.7 mm. 



Alt. 4.35, greatest diameter including lip 3.75 mm. 



Annam (Fruhstorfer). 



Except in color, this shell has little in common with H. 

 transitans, the concrescent angular and parietal lamellae and 

 the sculpture being notably diverse in the two species. 



4. HYPSELOSTOMA LAIDLAWI Collinge. PI. 31, figs. 14, 15. 



Shell dextral, conical, with last whorl dorsally grooved, sur- 

 face smooth, deeply umbilicated ; whorls 5, regularly increas- 

 ing; aperture CO-shaped, armature consists of four teeth, a 

 dorsal and a ventral one situated on the upper and lower 

 border of the peristome, and two smaller internal teeth, one 

 on the right and one on the left of the peristomial teeth ; peri- 

 stome thin, slightly reflected. Alt. and diam. i millim. (Col- 

 linge). 



