STREPTOSTYLA. 153 



23. S. VENTRICOSULA (Morelet). PL 30, figs. 87, 89. 



"Shell ovate, glossy, pellucid-fulvous. Whorls 5, nearly 

 flat, the last rather ventricose ; spire rather obtuse, short. 

 Columella calloused, spiral, white, prominent, arcuately con- 

 fluent with the basal margin, the truncation evanescent. 

 Aperture narrow, irregularly oblong, rounded basally more 

 than half the shell's length. Length 13, dram. 6, length of 

 aperture 8 mm." (Morelet). 



Yucatan: Merida (Morelet); Merida, Ticul, Tabi and Ux- 

 mal (Heilprin exped.). 



Glandina ventricosula MOREL., Testae, Noviss., i, p. 15 

 (1849). Streptostyla v., MARTS., Biologia, p. 97, pi. 5, f. 20. 



As Prof, von Martens has pointed out, this species differs 

 from S. cylindracea Pfr., with which it has been united. Fig. 

 87 is a copy of v. Martens' figure of the type specimen. A 

 series from the type locality and other places southward was 

 taken by the expedition sent out by the Academy in 1890. 

 An example from Uxmal is drawn in fig. 89. The first whorl 

 increases very rapidly, and 'at its termination is wider than 

 the adjacent part of the following whorl. The last whorl 

 widens much more rapidly than those preceding, the descent 

 of the suture being accelerated. The suture is very slightly 

 impressed and has a rather wide, clear margin below. The 

 sides of the last whorl are decidedly convex. The aperture is 

 lanceolate, the outer lip being rather strongly arched forward 

 in the middle. The columella is rather strongly twisted, and 

 bears a callous flange on its face. The shell figured measures, 

 length 12, diam. 5.8, aperture 8 mm., whorls 



24. S. YUCATANENSIS Pilsbry, n. sp. PI. 30, figs. 90, 91. 



Shell oblong, thin, amber-yellowish, subpellucid, very glossy, 

 with weak growth-lines. Whorls 5*4, the first one slightly 

 wider at its termination than the whorl below it, the rest 

 regularly increasing to the last, which in its later half de- 

 scends more rapidly. The suture is narrowly but rather 

 deeply impressed, and has only an extremely narrow linear 

 border. The last whorl is somewhat cylindric. The aperture 

 has the usual lanceolate shape. Outer lip strongly arched 



