26 University of Michigati 



From the variation in color and sculpture of mv specimens, 

 I very much question the specific rank of C. cuiiianciisc and 

 C. z'cncziiclcnsc, but have seen no authentic examples. Ch? 

 snbauricidatum Pfr. (1862) was also described from Cumana 

 (Bland). Specimens from Bland (original lot?) in the A. N. 

 S. P., show this to be a heavier form near C. bifoniic Pfr. 

 (1858), from Turks Island. Bahamas. Bland's locality is 

 probably incorrect. 



Tudora v/illiamsoni, new species 



Eighty-five specimens from damp, bare, rock faces along 

 quebradas in Aroa ^fountains (H, I, a, 23 (type). 24). The 

 most abundant shell present in these places, although Brachy- 

 podclla haiilcyaiia is almost as common. 



The shape of these shells is very similar to that of T. plica- 

 tula, but the 63^2 to 6^4 whorls are more convex, and the su- 

 tures more deeply impressed. The shells are heavier ; the 

 growth riblets are high, but compressed, and tend to occur in 

 pairs, or more rarely in groups of 3 or 4. The buttress-like, 

 sutural prolongations of the riblets are fine. Imt prominent. 

 The spiral, imibilical sculpture is present. Ijut is obscured by 

 the crowded ril)lets (fig. ii-8). The last whorl is free (so- 

 lute) for a very short distance. The aperture is almost circu- 

 lar. The peristome is quite broadly (.8 mm.) reflected on all 

 sides, but most prominently on the columellar lip. which is 

 often undulate. The parietal portion is produced into an an- 

 gular auriculation. which is adnate to the preceding whorl. In 

 adult shells, the reflection consists of several la\ers of varying 

 extent, so that a polyplex condition is produced. 'J'he color- 

 markings are similar to those of T. plicatiihi, but the higher 

 riblets give the shell a duller appearance. 



