364 Binney's Monograph of the Helices y 
o 
Greatest transverse diameter, more than one fourth 
of an inch. 
GrocnaPHICAL Distrieution. Inhabits Pennsyl- 
vania, the western parts of Virginia, and the States 
north of the Ohio River, where it is common. It is 
also found on the western sides of the Green Moun- 
tains, in Vermont. Further observations will un- 
doubtedly show that it inhabits some of the States 
south of the Ohio. 
_Remarxs. This bears a strong resemblance to the 
preceding species; the chief difference in their struc- 
ture seems to be, that while the whorls of that shell 
revolve about its axis at such a distance as to leave a 
considerable umbilical opening, they are in such near 
approximation, in this species, as to leave but a small 
perforation, which the narrow reflected lip is suffi- 
ciently wide to cover. In other respects, there is 
hardly an appreciable distinction ; but, as these differ- 
ences appear to be constant and: uniform, there is a 
propriety in keeping them separate. Mr. Say describ- 
ed this species with Rackett's description of HzLix 
mónodon before him, and considered it distinct. In 
most cabinets at this time, the two species are con- 
founded under the name of HeLIx fratérna. | 
Occasionally, the umbilicus is not entirely covered. 
À variety occurs in Illinois, which is only one-sixth 
of an inch in diameter. 
 Lister's figure, tab. 93, gi 94, I have no doubt is 
intended to represent this shell. Mr. Say’s descrip- 
tion was published in 1824. Férussac’s “ Prodromus” ` 
had already appeared, giving the name of HELIX con- 
véza to his species No. 101, but there was nothing to 
