of North American HelioidcB. 429 



"There is a small variety of this species, having about half the usual 

 diameter, and having its faces much more convex, which Mr. Lea has 

 described under the name of Caracdla Edgariana. Mr. Lea says, its 

 aperture has the form of H. hirsuta^ except that the superior and thick 

 part of the lip joins the tooth of the columella. We are not yet pre- 

 pared to admit this as a distinct species, though farther researches may 

 prove it to be so. The junction of the lip with the columellar tooth 

 seems to have been accidental in Mr. Lea's specimens; at least, we have 

 several specimens, corresponding to his in other respects, where this 

 character is wanting. Moreover, there is a large carinated variety of 

 H. hirsuta, from the same locality, which, so far as the aperture is 

 concerned, corresponds still better with Mr. Lea's description. His other 

 character, by which he distinguishes II. Edgariana from H. spinosa, its 

 being without cilia, is not constant, for fresh specimens of both large 

 and small -are well garnished with hairs, quite as abundantly as in II. 

 hirsuta ; and the difference in the two species is that in the latter the 

 hairs are erect, while in II. sjnnosa they are prostrate. Unfortunately 

 the engravings were made from specimens destitute of hairs." 



Tliere are two specimens in my cabinet which accord entirely 

 witli Lea's description, and also with fig. 2, PL XLIY. Terr. 

 MolL, the habitat of one nnknown, the other collected by Bishop 

 Elliott in Tennessee. I have seen no specimen, agreeing other- 

 wise with the type, in which the junction of the lip with the 

 parietal tooth is wanting, and believe it to be a good specific 

 character. 



IT. Edgariana differs also from JI. sjpinosa in the following 

 particulars : it is smaller, more elevated, and more convex 

 beneath. In form the parietal tooth is most like that of H. 

 stenotre?na, while that of H. spinosa is more nearly allied to 

 that usually prevailing in H. hirsuta. The whorls of II. spi- 

 nosa are flattened and exserted, the carinated edges of all being 

 seen, but in H. Edgariana the upper whorls are rather convex, 

 and defined by a well marked suture. Traces of hairs rarely 

 exist at the base of JI. spinosa^- and no scars indicating their 

 presence are visible on dead or denuded shells, whereas in H. 



