North American Helices, 5 



Among other characteristics of the Fam. Helicidae, H. & A. 

 Adams give : — " foot elongated, with the hind part simple and 

 pointed behind, not glandiferous" (II. 126) ; and of the Fam. 

 Stenopidae : '' foot long and narrow, abruptly truncated behind, 

 and furnished with a distinct, mucous, caudal gland" (11. 221) ; 

 yet I find in the lists above quoted the following inconsist- 

 encies : — 



Fam. Helicid^. Fam. Stenopid^. 



Anchistoma hirsutum Say. . Zonites stenotrema Fer. 



Iberus electrinus Gould, Helicella pura Alder, 



" sportella Gould. Discus Vaucouverensis Lea, 



Hygromia planorboides Raf. " planorboides Raf. 



Looking at the lists of species in the different genera and sub- 

 genera, I notice : — 



Anchistoma cereolus Muhlf. ) Polygyra septemvolva Say. 



" volvoxis Parr, j 



" major Biim. Mesodon albolabris Say. 



" palliatum Say. " appressum Say, 



" Troostianum Lea. Polygyra fastigiatum Say. 



Zonites fuliginosa Griff. Helicella fuliginosa Griff. 



The arrangement of the IN'orth American Helices by Albers 

 {Die Heliceen^ 2^ ed^) is certainly far more reliable and con- 

 sistent than that of H. & A. Adams. It is based on a better 

 knowledge of their forms and of the characters of the animals. 

 The lists* given by the former are not simply alphabetical, as 

 are those of the latter, but the affinities of the .species are con- 

 sidered, their habitats stated, and geographical distribution is 

 largely taken into account. 



The following extracts (to which I also add corrections, 

 printed in Italic letters) are from the above mentioned work of 

 Albers. 



* It will be understood that I extract from the lists given in both the works 

 referred to the names only (with few exceptions) of the species which occur in 

 Xorth America exclusive of the Pacific Coast and Mexico. 



