1911.] NATURAL SCIENCES OF PHILADELPHIA. 169 



and sometimes a little concave near the posterior orifice; outline of 

 the opposite side similar, but less convex. Tube circular in section 

 at "equator" and aperture, decidedly oval at posterior or anal orifice, 

 being compressed on the convex and less so on the concave side. 

 Aperture much larger than the other orifice, oblique, the peristome 

 thin. Anal orifice oval, decidedly wider than long, obstructed by a 

 circular callus within; edges unslit. 



Length 2.1 mm.; diameter at aperture 0.37, at greatest swelling 

 0.9 mm.; antero-posterior diameter at apex 0.27, lateral diameter 

 0.3 mm. 



Bowden, Jamaica. 



This is, I believe, the earliest member of the typical group of Cadulus 

 yet known. It is not unlike the recent C. exiguus Watson, but this 

 species is a little broader, the diameter contained 2£ times in the 

 length. In C. exiguus the shell is "contracted into a tube at either 

 end." In C. simrothi the posterior end only is tubular and the shell 

 is a little larger. 



