species would seem to be fully justified. Whether Dr. Amos 
Binney’s statement that the identity of Say’s ovalts and 
obligua ‘‘is rendered certain by the inspection of the original 
specimens labelled by Mr. Say” is to be allowed to over-rule 
the obvious application of Say’s description is a question for 
the systematists to determine. His decision has apparently 
been accepted without question by all the later writers on the 
subject. 
Just what Lea’s Swccinea retusa is, and how far it can be 
considered to cover the various forms commonly included 
under .S. ovalis Gld. is quite uncertain. The group is one of 
the most perplexing ones among our terrestrial mollusca. 
There is an enormous amount of variation and it seems almost 
impossible to draw any satisfactory specific lines from the 
slight and elusive characters afforded by the shells. Almost 
nothing has been done in working out the anatomical char- 
acteristics, and until that is done, it is questionable whether 
any satisfactory arrangement can be made. ‘There are sev- 
eral well marked varieties found in Michigan, which might 
be satisfactorily described from selected examples, but in any 
considerable number of specimens they seem to inter-grade 
almost without limit. Under the circumstances, it does not 
seem wise at present to attempt any formal characterization 
of them. 
As a group, S. retusa in its varying forms is found 
abundantly in all parts of the state. 
What may be considered, perhaps, as the typical form, 
characterized by a very Short spire and a patulous aperture 
expanding anteriorly, is very common. 
A larger form with a somewhat more elongated spire is 
probably the same as Calkins’ 5S. calumentensts. 
The form, which has been doubtfully referred to S. hig- 
ginsi, is smaller and more slender than the preceeding, and is 
quite characteristic of the northern part of the state. It has 
considerable resenblance to .S. elegans Risso and is probably 
the form that Cockerill has referred to that species. The 
large form from East Saginaw from the Lathrop collection 
(Naut. VII p. 127) seems to bear the same relation to this 
form that calumetensis does to retusa. A somewhat similar 
form, but with a more slender spire has been submitted for 
examination from Grand Rapids. It has a striking resem- 
blance to some of the west coast species. 
The form known as 'S. peor’ensis Wolf is typically quite 
sufficiently distinct from the usual form of 7c/wsa to be entitled 
to at least varietal rank. : 
An albino form also occurs occasionally. 
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