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THE NATURAL HISTORY SURVEY. 333 
about inthe fluid surrounding it. Those which occurred to me 
were found sticking to the shell of a female, although they 
were probably ot deposited by the same individual but by 
some other, as they were huddled together in groups accord- 
ing to their practice at this season.”* (Fig. 118, 2, 3). 
_  Radula formula: gotqsthtatatitistes 3-1-3); 
rhachidian (central) tooth very wide, low, the ends much 
rounded and produced, lower edge concave; center of concave 
portion supporting a large, tongue-shaped process; ends sup- 
porting, upon the anterior surface, four denticles, the two cen- 
ter ones small and the outer ones larger; the ridge supporting 
the denticles extending trom the distal end of the lateral lobe 
almost to the reflected cusp; reflection small, seven-cuspid, the 
cusps very small except the center one, which is rather large; 
“NI 
Fie. 120. 
Radula of AMNICOLA LIMOSA Say. (From nature, after Stimpson.) 
A, central tooth; 2, 3, lateral teeth. 
intermediate tooth subquadrate, the peduncle very long and 
somewhat enlarged at the distal end; body of tooth, at the 
inner side, with a peculiar knob-shaped projection; reflection 
low, wide, five-cuspid, the cusps subequal; inner cusp bluntly 
rounded, the rest acute; lateral teeth very long and narrow, 
the reflections small and multicuspid, the first having eighteen 
and the second thirty cusps (Fig. 120). 
Distribution: New England to Utah and Manitoba, Hud- 
son’s Bay to Texas. 
Geological distribution: Pleistocene; Loess. 
Habitat: Found plentifully in lakes and streams, on the 
muddy bottom, or on aquatic plants and submerged objects, 
Remarks: This abundant little species is easily recognized 
by its globose form. The animal is ‘very interesting in cap- 
tivity and wanders rapidly about the aquarium with a wabbly 
