GEOIvOGY OF LA SAIvIvE COUNTY. 



109 



on muddy bottoms, or among- the vegetation found in 

 our waters. Their food is vegetable, but they have 

 been found feeding- on decayed animal matter. Many 

 of the species are viviparous. I have taken V. con- 

 tectoides in the fall of the year, with the ovaries full 

 of the young, the shells showing distinctly three of 

 the bands peculiar to this species. The foot of the 

 animal is provided with an opercle which closes the 

 aperture when its owner withdraws into the shell. 

 In the spring- they deposit their young- in the mud. 

 The shells are turrited. 



VIVIPARA CON^ECTOIDES, W. G. BiNNEY. 



Shell large, globose, has five whirls, which are 

 finely striated, peristome acute and continuous, ting-ed 

 on the inner margin with a dark line, aperture subcir- 

 cular, color brownish horn. The body whirl has four 

 reddish bands, the last near the base, whirls very 

 bulging*. The beginning of new peristomes is marked 

 by prominent lines or ridges. Ivoc. Illmois River. 



Vivipara subpurpurea, Say. — Shell oblong-, whirls 

 five, wrinkled, apex obtuse, suture impressed, color 

 g-reenish with a purplish ting-e, spire leng-thened, shell 

 has three reddish bands, length three-fourths of an 

 inch. Found in the Illinois river. 



This species may be distinguished from any other 

 by the unusual expansion of the last whirl, and the 

 reddish bands, prominent in some specimens, but 

 obscure in others. 



Genus Melantho, Bowditch. — Melantho decisus, 

 Say. — Shell elongated, ovate, whirls six, peristome 

 acute, lines of growth plain, apex missing- in full 

 grown specimens, color green, aperture oval, oblique, 

 bluish within, length one and one-fourth inches. 

 Quite abundant in Fox and Illinois rivers, also in the 

 Vermillion river. 



