MOLLUSCA. 171 



at Rush Lake. They occurred in greater numbers off the former. As 

 mentioned al)ove, shells intergrading between the unicarinate and 

 non-carinate forms were found in abundance. 



Viviparidae. 



95. Campeloma decisum (Say). — A single specimen that has })een 

 referred to this si)ecies by ^Ir. Walker was brought up on the nets by 

 the fishermen, from about twenty feet of water, a little over a mile 

 nprth of Sand Point (1). The shell is heavily eroded and measures: 

 length 12mm., width 9mm., aperture length 7.5mm., aperture width 

 6mm. The epidermis is green with a tinge of red at the apex. 



96. Campeloma integrum (De Kay). — A single juvenile or dwarf 

 specimen of this species was brought up with Campeloma decisum 

 from about the same situation as that shell (1). Its epidermis is 

 copper-colored and its measurements as follows: length 19.5mm., 

 width 13mm., aperture length 10.5mm., aperture width 8.5mm. 

 Specimens were also found in considerable numbers buried in the 

 sand in shallow water along the shore of the ox-bow pond off the 

 Pigeon River (22), and in less abundance in the river itself, both in 

 the creek and river portions (21, 23). The epidermis of these shells 

 is green, sometimes tinged with reddish. Representative examples 

 measure: male, length 25mm., width 14mm., aperture length 12mm., 

 aperture width 10mm.; female, length 35mm., width 22mm.. aperture 

 length 19mm., aperture width 16mm. 



97. Campeloma rufum (Haldeman).^ — Seven specimens of this 

 species were obtained in the same manner and in the same locality as 

 Campeloma decisum and the first specimen of C. integrum (1). Five 

 are apparently females while two are males. They all have a copper- 

 colored epidermis and are quite heavily eroded. The largest of each 

 sex measure: female, length 16.5mm., width 13mm., aperture length 

 11.25mm., aperture width 8mm. ; male, length 12.5mm., width 8.5mm., 

 aperture length 6.5mm., aperture width 5mm. 



PELECVPODA. 



Unionidae. 



98. Lampsilis ventricosa (Barnes). — This unione was very abund- 

 ant all along the unprotected north shore of Sand Point (5). It also 

 occurred, but in lesser numbers, along the protected south shore (7) 

 of the Point, and on the unprotected, sandy, west shore of Stony Is- 

 land (5). All of the shells are the small Great Lakes form. The 

 beaks are considerably eroded. The largest male shell measures: 



