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 filosws, how- 

 ever, is a stout, very steeply conical species with coarser radial rib- 

 lets than auy other known American form, and totally different from 

 the low and delicate A. peninsula. 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, ftlnsux is a typical rock 

 Ancylus, like rivularis ; while the form from Florida is a true weed 

 dweller. 



The types of A. peninsiik? 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, n. sp. 



Shell ratber 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 striae, more distinct toward 

 the periphery. Length 6, breadth 4, alt. 1'S mm. 



Illinois River at Havana, 111. 



Types are no. 67791, coll. A. N. S, Phila, from lot no. 13542, 

 coll. III. 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. avails, 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 



