THE NATURAL HISTORY SURVEY. 343 
culiar aperture. Thespire isatrifleelevated. The S. depressus 
can be considered only a variety. This species is rather com- 
mon and widely distributed, being found in both the southern 
and western regions. 
Subfamily Pomatiopsine. 
Shell: Elongated, perforated; peristome continuous. 
Foot with lateral sinuses. Operculum paucispiral, without in- 
ternal process. Amphibious. (Tryon.) 
Genus POMATIOPSIS Tryon. 
Shell: Elongated, turreted, smooth, subumbilicated; aper- 
ture roundly ovate; peristome reflected; operculum corneous. 
Animal: With a broad foot, truncated before, rounded 
behind; tentacles short, pointed,subulate; rostrum large, round, 
blunt; verge large, broad, rather flat, coiled one and one half 
times on itself.. Jaw as in Ammnicola, but smaller. Radula 
formula 3-1-3; central tooth rather small, square, but a little 
broad at the base, where are two denticles, reflected cusp tri- 
dentate; laterals long and somewhat narrow, the inner lateral, 
however, being broader than the two outer, reflected cusp den- 
ticulate. The intermediate lateral is four-dentate, and the 
outer laterals five-dentate. 
Distribution: Eastern North America. 
KEY TO SPECIES OF POMATIOPSIS. 
pia SUE GlORsAtCH, ACUTE WHORIS SIK\<..6%. 4 scnae gees weak ns cen 6 lapidaria 
B. Shell conical, proportionately wider than A, whorls four 
dia test tay A ee Torey ROE iy tihtia neato hte Ghee als Re TSF cincinnatiensts 
141. Pomatiopsis cincinnatiensis Anthony, pl. xxvi, figs. 8, 9. 
Paludina cincinnatiensts ANTHONY, Bost. Journ, Nat. Hist., Vol. III, 
pt. land 2, p. 279, pl.iii, fig. 3, 1840. 
Shell; Conical, turreted; color greenish or brownish horn; 
surface shining, lines of growth crowded together; apex well 
rounded, obtuse, nuclear whorls smooth, polished; spire short 
conic in the male but more elongated in the female; sutures 
deeply impressed; whorls four, well rounded, somewhat ven- 
tricose; aperture orbicular; peristome rather thin, continuous, 
appressed to the body-whorl; last whorl very ventricose in the 
male but not so much so in the female; base of shell rounded; 
umbilicus narrow, deep. 
Length, 4.50; width, 2.30; aperture length, 1.50; width, 1.25 mill. (12478.) 9 
“ 5.00; “ 350; « “910; * 150 “ (12478)9 
CPB OO 62 VOID. ee “ 150; “ 125 “ (12478) 
