ASHFORD : NOTE ON BULIMUS HETEROSTOMUS. 131 



the last two occupying half the length of the axis. Edwards' 

 remarks (1. c.) "the shell has so much the appearance of Truncatdla 

 that I should be disposed to refer it to that genus " but for other 

 considerations. Reference to my complete figure above disposes 

 at once of this supposition. There is no appearance of trunca- 

 tion, the increase of the whorls from apex to base being gradual 

 and regular. 



The suture as seen in casts (which really represent the form 

 of the interior of the shell) is certainly "deep" but when the shell 

 is present the suture is not so pronounced in character, nor are 

 the whorls so convex. 



The striation is well described. I will only add that the 

 first whorl — as is so frequently the case in recent shells — is quite 

 smooth. In an immature specimen which shows the lines more 

 distinctly, I count about 90 on the fourth whorl; of these every 

 third or fourth or fifth is more raised than the intermediate ones. 

 The striae on the later whorls become rather coarser especially as 

 they approach the inferior suture. 



The aperture il described in the Monograph as having the 

 margin "slightly reflected." The figure (1. c.) appears to 

 represent a portion of an adult shell with the aperture but 

 partially formed. When fully developed the margin of the 

 peristome is broadly and boldly reflected, so much so as to form 

 a striking feature of the species. The Latin diagnosis should 

 therefore read — peristomate valde reflexo. 



The umbilicus is displayed in only one of my specimens. 

 Judging from the cast it may be described as small but con- 

 spicuous and partly covered by the reflected lip, but allowance 

 must be made for the presence of the shell which would lessen its 

 diameter. 



Length 8 mil, breadth about 4 mil, which agree closely 

 with the dimensions given in the Monograph. 



