358 THE CHICAGO ACADEMY OF SCIENCES. 



only for the reason that others may identify it, if collected in 

 this region by any student. 



148. Campeloma rufum Haldeman, pi. xxxvi, figs. 4, 6. 



Paludina rufa HALDEMAN, Mon., p. 3 of wrapper, pt. 3, pi. iii, fig. 1, 



1844. 

 Melantho gibba CURRIER, Amer. Journ. Conch., Vol. Ill, p. 112, pi. vi, 



fig. 3, 1867. 



Shell: Thick, but not heavy, elongately ovate or globose; 

 color olive green to light horn, especially near the sutures, 

 showing old peristome marks as in ponderosum ; beneath the 

 epidermis the shell is pinkish or reddish and the apex is pink- 

 ish; surface shining, polished, smooth, lines of growth numer- 

 ous, raised into conspicuous ridges here and there, crossed 

 by more or less distinct spiral striae; sometimes malleated'on 

 body-whorl; apex small, rounded, pinkish, eroded in some 

 specimens; spire obtusely conic, somewhat elevated; sutures 

 well impressed; whorls five and one-half to six and one-half, 

 convex on the sutures but rather flat-sided on the peripheral 

 portion of the whorl; last whorl (at the aperture) from two- 

 fifths to one-half the length of the entire shell; aperture ob- 

 liquely ovate, narrowed above, pinkish within, bluish-white on 

 the columella and near the peristome; peristome acute, sim- 

 ple, sigmoid, terminations joined by a bluish-white callus, 

 which is reflected over the parietal wall and covers the umbil- 

 icus; base of shell rounded. Operculum as \^ decisum. 



Length, 29.00; width, 17.00; aper. length, 14.00; width, 9.00 mill. (8859.)^ 



23.50; " 14.50; " " 13.00; " 8.00 " (10111.)c? 



20.00; " 13.00; " " 11.50; " 8.00 " (10111.)^ 



20.50; " 13.00; " " 11.50; " 7.75 " (10115.)^ 



27.00; " 19.00; " " 14.50; " 11.00 " (12866.)$ 



Animal: Not differing materially from decisum, 



Radula: As in decisum. 



Distribution: Connecticut and Massachusetts west to 

 Iowa, south to Tennessee and Alabama. 



Geological distribution: Pleistocene; Loess. 



Habitat: Found rather plentifully on muddy bottoms in 

 rivers and lakes. 



Remarks: This distinct and beautiful species is generally 

 confounded with decisum, but may always be distinguished by 

 the peculiar pinkish tinge of the substance of the shell beneath 

 the epidermis, and the pinkish apex. In form the shell much 

 resembles both decisum and obesum, as well as some forms of 



