THE NATURAL HISTORY SURVEY 271 
inner cusp and the eleventh and all that follow are of the usual 
form (Fig. 87). 
Genitalia: Not examined. 
Distribution: New England to California and Hudson Bay 
to Louisiana; Alaska (Randolph). 
Geological distribution: Pleistocene; Loess. 
Flabitat: Found in small colonies in ditches and clear 
patches of swamp. It prefers submerged pieces of wood. 
Remarks: This species is distinguished by its heavy spiral 
lines and long, acute spire. The animal is very rapid and de- 
cisive in its. movements. Several specimens, kept together in 
captivity, ate holes in each other’s shell for the lime for their 
own shells. This was at first attributed to cannibalism, but 
c k Ky , 
ghee y 8 ste 
b, ; tp é 4 17 “20 Ab 
Fig. 87. 
Radula of LIMN#A CAPERATA Say. (Original.) c, central tooth; 1-7, 
lateral teeth; 8, 9, modified marginals; 10, first true marginal; 12, 14, 17, 
intermediate marginals; 20, 25, outer marginals. 
upon investigation this supposition was found to be incorrect. ° 
It is quite abundant and is one of the neatest Limnzids found 
in this area. An egg mass of this species was laid March 16, 
1897. It contained forty-five eggs, distinctly nucleated, and in 
a jelly-like mass measuring 11 by 2 mill. _ 
‘On March 18th a second egg mass was laid, and on the 
Igththree more masses. On the 22d three individuals were seen 
in coitu, each one endeavoring to play the active part. Of the 
five egg masses laid each contained the following number of 
eggs: 42, 42, 35, 45, 28. The eggs were spherical in shape and 
very distinctly nucleated. One set of eggs was laid the morn- 
ing of the tgth, and at noon of the 20th embryos were seen 
slowly rotating about, propelled by numerous cilia. The 
writer regrets that through some accident which occurred while 
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