THE NAUTILUS. 57 



and there is another smaller one on the outer lip below the external 

 angle. 



Alt. 2, diam. 2.7 mm. 



Differs from lineata and Foxi in the trochiform shape, almost 

 complete freedom from spiral threads on the base, and in the acute 

 periphery. It has a small tubercle on the outer lip, as in L. Foxi, a 

 larger species with sculptured base, rounded periphery, scalloped 

 upper lip and different contour. 



The specimens were found associated with L. lineata. 



NOTES ON THE MOLLUSCA OF OWASCO LAKE, N. Y. 



BY FRANK C. BAKER. 



Recently the Chicago Academy of Sciences has received from Dr. 

 Howard N. Lyon, of Chicago, a fine lot of the shells of Cayuga Co., 

 N. Y., collected for the most part by himself about Owasco Lake and 

 River. Dr. Lyon was very precise concerning his data, and for this 

 reason a list of the species in the collection may be of value. 



For brevity I have used the following symbols for localities : 



* Near Auburn, in Owasco River. 



** Hayden's Mills, six miles below Auburn. 



f Foot of Owasco Lake. 



| Cascade. 



tt Marsh at foot of Owasco Lake. 



J I North end of Owasco Lake. 



1. Alasmodonta rugosa Barnes, *f July, 1893. 



2. Alasmodonta pressa Lea,*f in brook four miles north of Auburn, 

 July 1893 and 1882. 



3. Stropkitus edentidus Say.f 



4. Unio complanatus Solander,* in South Street Brook, July, 1879. 



5. Anodontopsis subcylindraceus Lea,* in South Street Brook, var- 

 ious collections from 1880 to 1885. 



G. Lampsilis hiteolus Lam,* July, 1883. 



7. Sphcerium simile Say,* in South Street Brook, 1882. 



8. VaUonia pulchella Miiller, April, 1882. 



9. Polygyra albolabris Say.| 



10. Polygyra thyroid es Say, var. buccidenta Gould. \ 



