THE NAUTILUS. eT 
Pupa armifera Say. 
Pupa contracta Say. 
Vertigo ovata Say. 
Vertigo gouldii Binn. Quite abundant apparently, and exhibiting 
some considerable variation in size. A single albino example is 
included, of which Dr. Sterki writes “This is a very interesting 
and valuable specimen ; the only true albino among many thousand 
specimens of our Vertigos I have seen.” 
Vertigo ventricosa elatior Sterki. Not heretofore known from 
Michigan. 
Vertigo pentodon Say. Vertigo curvidens Gld. 
Ferussacia subcylindrica L. 
Succinea oblivua Say. Suecinea peoriensis Wolf. 
Succinea avara Say. Succinea sp. 
Succinea ovalis Gld. Suceinea sp. 
There are four forms of Succinea in the collection, which group 
around 8. ovalis Gld. as a type. ‘The first is the form usually called 
ovalis characterized by the short; rather blunt spire, elongated body 
whorl and effuseaperture. The second is the peoriensis of Wolf, a 
very widely extended form in Michigan and easily separated from 
the “ovalis” by reason of the shorter body whorl and more nearly 
oval aperture, which though somewhat narrowed posteriorly lacks 
the patulous expansion anteriorly so characteristic of the former. 
The third resembles ovalis in the shape of the aperture, but is a 
more slender shell and has the spire more elongated than either the 
preceeding forms. It appears to range generally over the State and 
is the same form noticed as “S. higginsi Bld.” in my catalogue of 
Michigan shells (Naur. VI, p. 19). 
The fourth form is quite remarkable. Having the general shape, 
characteristic of the group, it far exceeds them all in dimensions, 
equalling in length a good sized S. obliqua Say. These shells were 
labeled by Dr. Lathrop as “S. sillimani Bld.?” They agree sub- 
stantially in form and size with figures of that species given by 
Binney. Some individuals, however, have the spire more produced, 
resembling in that respect the figures of S. hawkinsi Bd.; but the 
suture is not impressed to the extent represented in that species. 
None of them have the blunt apex, which seems to be characteristic 
of S. haydeni W. G. Binn., though fully equalling that species in 
size. Cockerell (Naur. VI, pp. 23 and 29) refers all these forms to 
the S. elegans Risso of Europe. — It is possible that these specimens 
