LYMNEIDA OF NORTH AMERICA. 147 
NeEvADA: Rare specimens are found semi-fossil in the Humboldt sink in 
the Lahontan area (Call). 
Ontario, CANADA: Sand and gravel pits, Niagara Falls; Leda clay, ten 
miles below Ottawa city (Bell). 
UraH: It abounds, as a semi-fossil, in Sevier Desert (Call, Mollusca of 
Great Basin). 
EcoLtocy: Found usually in more or less stagnant spots of ponds 
and rivers about decaying vegetation. In ponds it may be found float- 
ing among pond weeds with its foot applied to the surface of the water. 
A shore bordered with reeds and cat-tails is a favorite locality. Also 
found on, and in the vicinity of, rotten fruit and vegetables, and fre- 
quently seen feeding on the dead bodies of various animals. In the 
small bays and inlets of Lake Ontario, this species is very abundant. 
It has been noted that early in the year, about May or June, stagnalis 
is found only in small patches of water near the shore, while later in 
the year, in August or September, it may be found in abundance float- 
ing in the open water of these bays, particularly in the vegetation which 
is so common at this time of the year. It breeds in the fall. 
“In a small pool along Bitter Root River. A large spring supplies 
the pool with clear, fresh water. (Elrod, Montana.) 
“In lakes, feeding upon weeds. (Sargent, Minnesota. ) 
“Outlet of Lake Tahoe, Placer County, Cal., 6247 ft. alt. (Cooper. ) 
“The specimens from the prairie region are often very well grown 
and robust, the shell being thick and showing strong growth lines. 
Some specimens from pools at Dufferin measured 56 by 26 mill.” 
(Dawson, Manitoba. ) 
Although generally supposed to be a vegetable feeder, stagnalis 
is known not only to feed upon dead animals, but instances are on 
record of its attacking living animals, especially fish (stickleback) 
which have been confined with them in the aquarium.t The writer 
has observed it adhering to rotting vegetables, dead dogs, cats and 
other animals in the Erie Canal, at Rochester, N. Y. Mr. William 
Nelson? records the presence of a pale violet liquid, which is discharged 
by the animal when irritated and sometimes when lifted from the water. 
The same phenomenon has been observed by the writer in many of 
the American forms. 
Some interesting experiments in raising appressa from the egg 
have been made by Dr. H. A. Pilsbry at the Academy of Natural 
Sciences of Philadelphia. The specimen from which the eggs were 
obtained was a large, fat individual of five whorls, from Buffalo, N. Y., 
tUllyett, Sei. Gossip, XXII, p. 24, 1886. 
Journ. ‘Conch: I p: 206, 1878. 
