PSEUDOGLESSULA. 167 



and the more distinct the keel the more does the lower sur- 

 face differ from the upper by weaker sculpture and brighter 

 gloss. The largest shell, a banded one, measures 35 mm. 

 long, 17 wide, the mouth 15.5 mm. long. 



14. P. PRESTONI Smith. PI. 61, fig. 93. 



Shell ovate, produced above, thin, deep olive-brown, semi- 

 pellucid; spire obtuse at the apex. Whorls 7, obliquely, 

 closely, delicately ribbed, moderately convex, the last en- 

 circled with an obtuse keel at the periphery, more glossy be- 

 low the keel, the ribs less strong there; scarcely descending 

 in front. Aperture inversely ear-shaped, bluish or opalescent 

 inside, its length about three-sevenths that of the shell. 

 Lip thin, arcuate ; columella twisted, thickened in front, pale, 

 subtruncate, joined to the outer lip by a very thin callous. 

 Length 28, diam. 13 mm. ; aperture 12 mm. long, 7 wide. 

 Another specimen is 30 mm. long and 13 broad (Smith) . 



German East Africa: Ukami, about 100 miles south-west 

 of Zanzibar. 



Pseudoglessula prestoni SMITH, Proc. Malac. Soc. Lond. 

 vi, p. 68, f. II (March, 1904). 



''This species is very like P. kirki Craven, but differs in 

 form and in having one whorl less. The spire in that species 

 is a trifle more slender, the body-whorl smaller, and the 

 columella is so reflexed as to form a narrow umbilical fissure. 

 There is also the difference of color in the two forms. Named 

 after Mr. H. B. Preston, from whom the specimens were ob- 

 tained " (Smith). 



15. P. GRACILIOR Smith. PL 61, fig. 92. 



Shell similar to P. prestoni, but narrower, lengthened, pale 

 brownish. Whorls 8, a little convex, obliquely delicately 

 costulate. Aperture slightly more than a third the total 

 length. Length 28, diam. 11.5 mm.; aperture 10 mm. long, 

 6 wide (Smith). 



German East Africa : Ukami, about 100 miles southwest of 

 Zanzibar., 



P. gracilior SMITH, Proc. Malac. Soc. Lond. vi, p. 69, f. 

 Ill (March, 1904). 



