NATURAL SCIENCES OF PHILADELPHIA. 335 



to high elevations on the mountains in east Tennessee and western 

 North Carolina. I am indebted to Miss A. E. Law for all the 

 specimens of this species I have seen. 



Zonites acerra, Lewis. 



In the paper quoted above, on page 190, mention is made of a 

 shell supposed to be a variety of Zonites ligerus of W. G. Binney. 1 

 The shells when first brought to notice were supposed to be 

 undescribecl, but having characters which belong equally to de- 

 missus and ligerus (Binney) it was treated as a variety of ligerus, 

 though the name acerra was suggested as applicable if new. 



I am induced by a careful study of this form to regard it as 

 having quite as valid a claim to be regarded a distinct species as 

 demissus has, it being different from that species in several im 

 portant particulars which, so far as I have traced them, seem to 

 be constant. The notes and figures given, relative to this species, 

 render a formal description of the species unnecessary. 



The shell has a cubic capacity more than four times that of 

 demissus, being less pale, usually more translucent, and the opaque 

 portions have a decided Canary-yellow tint. 



This shell is found in the elevated lands in east Tennessee and 

 western North Carolina, and no doubt has been circulated as 

 demissus. 



Among the numerous land shells collected by Miss Law, in 

 Knox and Monroe Counties, Tennessee, I found a few specimens 

 of a Zonites very like Anthony's cerinoidea with this difference 

 the shells have two internal lamellar teeth, in some cases arising 

 obliquely within the aperture and pointing outwardly, differing 

 somewhat in form from the teeth of gularis. The question arises, 

 is cerinoidea dimorphic as to the presence or absence of the internal 

 teeth ? I have numerous examples showing that the internal teeth 

 of gularis are by no means constant. If the shells I here com- 

 pare to cerinoidea are really a variety of that species, they may be 



1 I speak of "Zonites ligerus of "W. G. Binney," because I am aware that 

 there are traditions respecting the species now generally accepted as ligerus 

 and intertextus, which call for a different nomenclature. The shells now 

 known as intertextus are the traditional " Helix ligera" of Say ; the tradition 

 undoubtedly having its origin with Mr. Say, who surely ought to have the 

 credit of knowing his own species. This understanding of the matter makes 

 it quite easy also to recognize the claims of Mr. Lee to the species he 

 described as Helix Wardiana. 



