]}'.)•> THE CHICAGO ACADEMY OF SCIENCES. 



Length. 



Breadth. 



Aperture k 



:ngth. 



Breadth. 





15.00 



8.00 



9.00 





3.75 



mill. 



Type. 



11.50 



6.00 



5.50 





2.25 



" 



" 



14.00 



7.00 



8.50 





3.50 



" 



Squaw Island 



11.00 



6.00 



6.50 





3.25 



" 



" 



13.00 



7.00 



8.00 





3.75 



" 



" " 



13.50 



7.00 



7.50 





3.50 







Types: Three specimens, Smithsonian Institution, No. 11806L 

 Type Locality : Niagara River, Levviston, New York. 

 Animal, Jaw, Radula and Genitalia: Not examined. 

 Range: New York and Ontario. Fusiformis appears to be a 

 characteristic race of the Great Lakes, no specimens having been seen 

 from any locality outside of this drainage. It is, therefore, confined 

 to the Canadian region. 



RECORDS. 

 United States. 

 New York: Squaw Island, Niagara River, Erie Co. (Letson; Nason; 

 Miss Walker) ; Lewiston, Niagara Co. (Lea; Nicklin) ; rapids above the Ameri- 

 can Falls, Niagara (Miss Walker). 



British America. 

 Ontario: Ottawa, Carleton District (Hinkley). 



Geological Range: Unknown. 



Ecology : Not recorded. Evidently modified by the influence of 

 rapid flowing or rough water. 



Remarks : Niagarenis differs from catascopium in its smaller 

 sise, generally more solid shell, more fusiform shape, less impressed 

 sutures and hence more flat-sided whorls (especially the body whorl) 

 and in its more elongated aperture ; the columellar callus is heavier in 

 adult specimens, but the columellar plait is much less conspicuous. 

 This is a neat little shell, usually quite distinguishable from typical 

 catascopium. Binney (p. 50) places fusiformis in the synonymy of 

 desidiosa (obrussa) but in this he was in error, a fact made clear by an 

 examination of Lea's types, which have the heavy spiral sculpture of 

 catascopium. The umbilical chink is not always tightly closed, the im- 

 mature shell frequently showing quite a chink. In the type lot, two 

 specimens, immature, show a small umbilical chink, while one specimen, 

 adult, is quite imperforate. The specimens from Squaw Island, illus- 

 trated on plate XLII, are the same as the type specimens and well il- 

 lustrate the form of the race. Specimens from Niagara Falls are 

 the same as are also certain very immature shells from Ottawa, Canada. 

 Certain narrow forms of catascopium from Pine Lake, Charlevoix Co., 

 Michigan, somewhat resembles niagarensis, but the whorls are rounder, 

 the sutures deeper and the aperture is much rounder. Niagarenis 



