2l8 LAKES AND RIVERS, 



small brown and white specks, long tentacles ; the 

 foot has a narrow edge of yellow. The shell is 

 2 long and i broad ; there are 7 or 8 whorls 

 convex, and bulging out in the middle ; the colour 

 like the last-named species; the epidermis is thin. 

 There are several varieties, fragility albinus, &c. It 

 is found throughout the Kingdom. L. palusms 

 (Miiller) has a dark-gray body, with a tinge of violet- 

 brown, covered with black and yellow spots. The 

 shell is oblong, of a dull colour, sometimes tinged 

 with violet, sculptured as is stagnalis, but the spiral 

 ridges are more prominent. There are several 

 varieties. Z. truncata (Miiller) has a dark-coloured 

 body, lighter on the lower side, with fine black specks ; 

 the tentacles are short and slender. The shell is 

 oblong-conic, turreted, solid for its size, sculptured as 

 in the last species. There are several varieties of 

 this species. The typical size is in length 0*4, in 

 breadth 0*2. L. glabra (Miiller) has a dull gray 

 body covered with minute spots ; the eyes are placed 

 on prominent tubercles. The shell is cylindrical, 

 with 7 or 8 whorls, rounded, not very convex ; the 

 spire ends in rather a blunt point. It is sparingly 

 distributed, and inhabits shallow pools. 



The genus Ancylus of Geoffrey, has the body oval, 

 conical, slightly twisted ; the head is large. The re- 

 spiratory pouch forms a short tube. The shell is 

 hood-shaped. This genus is related to Limncea. 

 They inhabit rapid and still waters. The food of 

 the Ancyli is algae or confervse, and decayed vegetable 

 matter. They are also said to swallow a portion of 

 sand to assist their slow digestion ; they can live a 



