North American IlelicidoB. 35 



"BreacUli rather more than three-tenths of an inch. Inhabits the 

 North-West Territory," 



The annexed is a fac-simile of Say's figures. I cannot ac- 

 quiesce in Dr. Binney's opinion that 11. jyorcina 

 Say " appears to correspond to II. hirsuta Say in 

 an immature state." 



Say originally described II. hirsuta in Nichol- 

 son's Encyclopedia (1816), the description was 

 also published in the Journal of the Academy in 

 181T. In the same Journal (1821), he enume- 

 rates it, among other species observed in the "Western regions, 

 as being " common as far as Council Bluff." 



It seems to me in the highest degree improbable that Say 

 would fall into such an error as to describe a young hirsuta 

 not only as an adult shell, but even as a different species. 



Unfortunately no authentic specimen is now in existence, and 

 no record of the examination of one by any of Say's contempo 

 raries. Dr. Binney does not refer to the species in the Boston 

 Journal, and in the Terr. Moll, only in the few words above 

 quoted. De Kay and Pfeiffer merely copy Say's descrip- 

 tion. 



That Say's figures accurately portray the species, may be 

 inferred from the correctness of those of the other shells repre- 

 sented on the same plate. The outline figure, showing the 

 natural size, exhibits an aperture by no means agreeing with 

 that of an immature hirsuta, having rather more than four 

 whorls. 



Say describes the epidermis of H. porcina as rugose, with 

 minute, very numerous bristles. The epidermis of hirsuta and 

 fraterna is not mentioned, but the one species is said to be 

 " covered with short, numerous, rigid A«^V5," and the other to be 

 "minutely hirsute." In his description oi II. palliata, say 

 uses the expression " epidermis fuscous, rugose, with very 

 numerous minute tuberculous acute prominences ; " he was 

 unacquainted with the character of the epidermis of H. infiecta 



