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THE NAUTILUS. 139 
This is by no means rare in collections of fresh-water shells from 
Florida, but is generally labelled “A. filosus Conrad,” probably on 
account of the conspicuous radial sculpture. Conrad’s filosus, how- 
ever, is a stout, very steeply conical species with coarser radial rib- 
lets than any other known American form, and totally different from 
the low and delicate A. peninsule. It is from the Alabama River, 
where it is found living on Melanians. This fact, together with the 
texture and form of the shell, indicate that ji/osus is a typical rock 
Ancylus, like rivularis ; while the form from Florida is a true weed 
dweller. 
The types of A. peninsule were collected by the editors of this 
journal in Salt Creek, one of those sparkling streams of ‘‘sulphur 
water” so characteristic of Florida, arising from great brimming 
springs and feeding the St. John’s and other rivers. Salt Creek is 
the northernmost stream flowing into Lake George on the west side. 
The Ancylus lives on long water-grass, and is abundant. 
Ancylus eugraptus Pilsbry, 7. sp. 
Shell rather fragile, oval, the right side less arcuate than the left ; 
rather elevated, the apex slightly behind and to the right of the 
middle, somewhat obtuse, with an indistinct apical depression or 
scar, posterior and right slopes straight, anterior and left feebly 
convex. Translucent horn colored and glossy when cleaned, with 
a blackish coating when collected. Surface with faint growth-lines 
and very fine, somewhat irregular radial strize, more distinct toward 
the periphery. Length 6, breadth 4, alt. 1:3 mm. 
Illinois River at Havana, II]. 
Types are no. 67791, coll. A. N.S., Phila., from lot no. 13542, 
coll. Ill. State Lab. Nat. Hist. 
This species, while resembling A. obscurus and A. fuscus some- 
what, differs from both in the sculpture. The apex is far more ex- 
centric than in A. borealis or A. ovalis, both of which are very small 
species. A. filosus is far rounder, more steeply conic, and has 
stronger radial riblets. In A. rivularis the apex is much more 
strongly recurved, and the slope behind it notably concave. 
ISAAC LEA DEPARTMENT. 
[Conducted in the interest of the Isaac Lea Conchological Chapter of the Agassiz Associa- 
tion by its General Secretary, Mrs. M. Burton Williamson. | 
One of our new members in a letter to the General Secretary 
writes as follows in reference to collecting Mollusks in Winter in 
