356 THE CHICAGO ACADEMY OF SCIENCES. 
Genus CAMPELOMA Rafinesque, 1819. 
Paludina, Vivifara and Melantho of authors. 
“Shell: Thick, solid, ovate, imperforate, spire produced; 
whorls rounded, smooth, covered with an olivaceous epider- 
mis; peristome simple, continuous.” (W. G. Binney.)* 
Animal; With a large, broad, rather thin foot, “much 
produced beyond the snout and slightly auricled in front. 
Color rather light, in reddish (orange) spots on a palish white 
ground. Head of moderate size, snout small. Lingual teeth 
smooth or only minutely crenulated at their apices. Cervical 
lappets of moderate size, but not forming regular tubular . 
aquiferous ducts; the right one plicated. Branchial lamine 
elongate-triangular, equal in size and arranged in a single 
straight row both at base and tips.” (Stimpson.)tT 
“The operculum is elongately-ovate, somewhat produced 
anteriorly and curved; thin, corneous, subconcentric, with sim- 
ple nucleus near parietal wall; reddish or light brown.” (Call.) 
Disribution: The United States east of the Rocky Moun- 
tains. 
KEY TO SPECIES OF CAMPELOMA. 
A. Shell reddish or pinkish under the epidermis, especially the 
APSR: 5's siscFs oeha y eaght spas aula where ke etal Sipe ely tae i rufum 
B. Shell dark olivaceous or greenish, chalky-white beneath the 
epidermis. 
a. Spire very short, stumpy; aperture longer than spire, 
produced into a sort of channel at the upper (poste- 
rior) part; shell'very ponderous’... (4... Js. v<h. eae ponderosum 
b. Spire rather long, aperture and spire of equal length, 
aperture not produced. 
1. Whorls rounded; shell generally ovate, rather thin, 
spire somewhat depressed, aperture rounded ...... decitsum 
2. Whorls rather flattened; shell generally elongated, 
solid; spire produced, aperture sigmoid.......... subsolidum 
147. Campeloma ponderosum Say, pl. xxxv, fig. 9. 
Paludina ponderosa Say, Journ. Phil. Acad., Vol. II, p. 173, 1821. 
Paludina regularis LEA, Trans. Amer. Phil. Soc., Vol. IX, p. 15, 1844. 
Melantho nolani Tryon, Con. Haldeman, Mon., p. 25, pl. xii, figs. 
10-11, 1870. 
Shell: Very heavy and solid, globosely ovate; color gen- 
erally greenish, but blackish in old specimens and showing 
old peristome scars; surface shining, polished, smooth, lines of 
*L. and Fr. W. Sh., pt. 3, p. 36. 
tSee Bull. Washburn Coll. Lab. N. H., Vol. I, No. 5, p. 153. 
