THE NATURAL HISTORY SURVEY. 409 



black, irregular spots which show through the shell; foot 

 roundly elongated, 18 by 11 mill., head broad, auriculated; ten- 

 tacles large, flat, long, triangular; heart pulsations slow and 

 regular; thirty-four per minute. The animal is slow and de- 

 liberate in its movements. 



Jaw and radula: Not examined. 



Genitalia: Not examined. 



Distribution: European; greenhouse and lily-pond in Lin- 

 coln Park, Chicago. 



Geological distribution: Pleistocene. 



Habitat: Similar to that of the larger Limnaeas. 



Remarks: Some time ago Mr. Herbert E. Walter, In- 

 structor in biology in the North Division High School, Chi- 

 cago, brought to the writer several specimens of a Limnaea 

 which was new to the fauna of the United States. Upon 

 inquiry the locality was given as the propagating greenhouse 

 in Lincoln Park. Several days later Miss Marie La Grange, a 

 pupil in the North Division High School, found a number of 

 the same species in a lily pond in the Park, the water of which 

 was artificially heated to give the necessary warmth for certain 

 tropical plants, the temperature being above 90 Fahr. 



Comparison with the shells in the Academy's collection 

 showed the species to be Limntza auricularia, and an inquiry of 

 the park gardener brought to light the fact that certain plants 

 had been recently imported from Belgium. This information 

 at once removed the mystery surrounding the sudden appear- 

 ance of this shell in the Park, and shows how easy it is at the 

 present time to transport a species from one continent to an- 

 other, especially if it be a pulmonate. The shells of auricularia 

 are about an inch in length, of a deep corneous color, and are 

 rather thin. When alive, the mantle of the animal is seen 

 through the shell to be made up of dark and light spots ar- 

 ranged irregularly. The animal appeared rather active, mov- 

 ing about the aquarium with a steady, gliding motion. 



163. Amnicola walker! Pilsbry. 



Amnicola walkeri PILSBRY, The Nautilus, Vol. XII, p. 43, 1898. 



Shell: "Thin, narrowly umbilicate, conic, shaped like Lyo- 

 gyrus brownii Carpenter; slightly yellowish corneous; thin, 

 smooth, with faint growth-lines. Whorls four, very convex, sep- 

 arated by deeply constricting sutures, the last whorl rounded 

 below; apex obtuse. Aperture oblique, rather small, mainly 



