72 HELICID^. 



accessible for comparison, and presenting only a limited 

 amount of variation, whicli in any other genus would 

 not produce inconvenience, there has nevertheless been 

 a good deal of imcertainty in the identification of it. It 

 has been taken for both the species which we consider 

 synonymous, as its characters may have leaned to one or 

 the other. It is thought to be Succinea campestris, Say, 

 by those who consider this to be a northern species ; and 

 it is unquestionably Succinea totteniana, Lea.' It is 

 thus the representative of four nominal species, and per- 

 haps of even more. That we have made no mistake, 

 and that the shell described by Mr. Say as Succinea 

 ovalis is the same as that called by Drs. Gould and 

 Mighels Succinea campestris, is rendered certain by 

 inspection of the original specimens labelled by Mr. 

 Say, and by others from the contemporary collections of 

 Mr. Hyde, and of Dr. Griffith, as well as by familiar 

 acquaintance with the cabinets of the two former. That 

 Succinea ovalis, Say, and Succinea obliqua, Say, are 

 synonymous we infer from numerous specimens collected 

 in many parts of the country. 



[ ' There seems to be good reason for regarding Mr. Lea's S. totteniatia as 

 a distinct species. It is a local species, confined, so far as I can ascertain, 

 to tlie New England States, and east of the Green Mountain range. Com- 

 pared with S. obliqua, the following characters appear constant. It is a 

 thinner and more fragile shell, proportionally more ventricose in form, with 

 a shorter spire and larger aperture ; and it has a decided green color almost 

 unshaded with yellow, while in S. ohliqiia the amber yellow predominates. 

 It is hardly to be supposed that either the colder climate or the want of lime 

 could account for a group of such differences, so constant. — g.\ 



