THE NATURAL HISTORY SURVEY. 



355 



tooth with a quadrangular base of attachment, rounded above 

 and below, reflected portion small, nine-dentate, the central 

 cusp the largest; intermediate tooth longer than wide, some- 

 what sole-shaped, nine-dentate, cusp wider than high; lateral 

 teeth longer than wide, the second nine-dentate and the third 

 seven-dentate. The writer counted 55 rows of perfect teeth in 

 one membrane (Fig. 134). 



Distribution: Eastern United States from Michigan to 

 New York and Florida, and from South Carolina to Arkansas. 



Geological distribution : Pleistocene; Loess. 



Habitat: Found in lakes and rivers, where there is a 

 muddy bottom, more frequently where there is a quantity of 

 grass, in water from a foot to two or three feet in depth. 



Remarks: This is a very common and beautiful species. 

 It is unlike any other mollusk found in this region, the four 

 spiral bands easily distinguishing it. In some localities it is 



FIG. 134. 



Radula of VIVIPARA CONTECTOIDES, W. G. Binney. (Original.) C, 

 central tooth; 1, intermediate tooth; 2, 3, lateral teeth. 



the predominating form, and thousands of dead shells may be 

 found upon the shores of such localities as Wolf and Calumet 

 lakes. It is most interesting in an aquarium, and readily 

 moves about, its long tentacles and rounded rostrum extended 

 to their full length, the latter bent downward, the former feel- 

 ing about nervously and the shell swinging from side to side. 

 The young have a foot almost black in color, with large, irreg- 

 ular white spots on the under side; they are very active. The 

 shell is very variable in regard to the presence of the bands, 

 some specimens being perfectly plain and others but faintly 

 banded. It seems to be pretty widely distributed, but is most 

 common in the southern region, in the chain of lakes. 



