BULINUS. 171 
4. B. BERLANDIERIANUS, W. G. Binney. 
Plate 7, fig. 17. 
Shell cylindrical, smooth, whitened, rather 
thick ; whorls five, the upper ones narrowly 
flattened, the lower one comprising more than 
15—17 of the total length of the shell; quite 
compressed ; aperture very long, narrow, colu- 
mella simple, with a slight callus. 
Length 17, diam. 8 mill. 
Near Matamoras, Texas. 
5. BULINUS TENUISSIMUS, Lea. 
Plate 7, fig. 16. 
Shell subfusiform, exceedingly thin, very 
fragile, transparent, shining, whitish; spire 
produced; sutures scarcely impressed ; whorls 
four, slightly convex, the last one very large 
and somewhat compressed; aperture large, 
(87) 
