110 THE NAUTILUS. 
This is one of the most distinct and remarkable Unios in the 
United States. In its general structure, the hinge characters, the 
row of dorsal cicatrices, the incipient pallial sinus, and the gaping 
shell it shows relationship with Unio tenuwissimus, and its nacre is 
something like that of this species, but the female shell is consider- 
ably swollen in the post-basal region, and it reminds one a little of 
a short, compressed, female Unio rectus. The posterior opening, 
however, is its most remarkable character, commencing about mid- 
way up the end of the shell, and extending nearly to the ends of the 
laterals. This gap ends abruptly above, and less so below; the 
edges of the shell are reflected outwards, and considerably lamel- 
lated, and in old shells the remains of former reflected apertures 
may be seen. The opening in a fully adult shell is about one-tourth 
of an inch wide and one and one-fourth inch in length, and is as 
distinct as that of Schizothwrus nuttalli of the west coast of the 
United States, and occupies about the same relative position that it 
does in this marine bivalve. It may possibly group with Unio ten- 
uissimus, but it is quite likely that it will have to be made the type 
of a new group, related to that species, to the a/atus and tampicoen- 
sis groups. 
I desire to thank Mr. Chas. T. Simpson for the valuable aid given 
in the preparation of the above description and remarks. 
NOTES ON QUEBEC PUPIDH AND OTHER SHELLS. 
BY A. W. HANHAM, WINNIPEG, MAN, 
My Quebec Pupide have just been looked over and separated for 
me by Dr. V. Sterki, to whom I am under many obligations for 
this labor of love. As a result my list of species, as far as these 
small things are concerned, requires some corrections and additions. 
The following are the species taken, instead of as recorded on 
page 101, of the last volume of THE Nauriius :— 
Pupa armifera Say. As already recorded. 
Pupa pentodon Say. As already recorded. 
Sphyradium edentulum Drap. Not uncommon; Isle d’Orleans. 
and St. Joseph’s de Levis. 
Vertigo ovata Say. As already recorded. 
