88 BemarTcs 07i Certain Species of 



species were at that time apparently unknown to American 

 conchologists. Dr. Binney makes no mention of tbem in the 

 Terr. MolL ; and Dr. Gould even omits them in vol. iii. (1857), 

 although he inserts descriptions of additional species, " so as to 

 embody all the species at present known." Mr. W. G. Binney 

 admits them in the Supplement (1859) to his father's work. 



In 1859, Mr. Wm. Cooper collected at Nassau, New Provi- 

 dence, numerous specimens of a species apparently identical, 

 though varying somewhat from that which inhabits Bermuda.* 

 Neither Mr. Binney nor I have received, or even seen speci- 

 mens from Texas of any of the species belonging to this group. 

 Before examining the strictly North American species in 

 detail, I may explain that I consider II. cereolus Miihl. and II. 

 septemvolva Say to be distinct, — that the Bermuda shell is the 

 H. microdonta Desh, and that the species from Florida, now 

 known here as microdonta, has not been described. In the fol- 

 lowing pages I describe it under the name of II. Cavipenteriana. 

 As to H. vol/voxis Parr. I think that it is no more than var. of 

 II. sejptemvolva. 



H. sejytemvolva, as described by Say, cannot be misunder- 

 stood, — it occurs only, I believe, in East Florida, and especially 

 at and in the vicinity of St. Augustine, — for many fine speci- 

 mens collected there, I am indebted to Mr. O. M. Dorman. 

 It is variable in size, but distinguished by its sharp carina and 

 open umbilicus. In a specimen with Si- whorls (dlam. maj. 14 

 mill.), the width of the actual umbilical opening is 2 mill. The 

 penultimate beneath is generally half covered by the last 

 whorl. Tiie very small var., called the onale by Say, is com- 

 paratively rare. 



The four examples preserved at Philadelphia, said to be 

 authentic, are of the form described. 



* H. paludosa Pf. {lingulata Fer.), an inhabitant of Cuba and Jamaica (rare 

 in the latter island), belongs to this group, bnt is readily distinguished by its 

 rugose upper surface, and small parietal tooth which is unconnected with the 

 margins of the peristome. 



