SNAILS AND LIMPETS. 



183 



useful food for the fish. A drawback in keeping these snails 

 in the aquarium is their habit of escaping from it, and 

 dying outside of it for want of water. The tanks, therefore, 

 in. which they are confined should be covered. The body of 

 the animal is a pale brown, tinged with green. The tentacles 

 are flat, triangular, and placed almost at right angles with 

 the sides of the animal. The eyes are black, and plainly 

 seen. The shell is obliquely-ovate, and of a glossy dark 



Fig. 122. LlMN/EA PEREGRA. 



yellowish horn-colour. There are five whorls, the body-whorl 

 taking up more than three parts of the length of the shell. 

 The spire, which is more or less produced in difEerent in- 

 dividuals, occupies about a quarter the length of the shell. The 

 aperture is large and oval, and the outer lip is a little 

 . reflected. This snail is found in the slow-running and 

 stagnant water of nearly every, if not every, part of Britain. 

 It lays from sixty to eighty eggs, and incloses them in an 

 elliptical capsule. It produces many such capsules in the 



