298 



MANUAL OF THE MOLLTJSCA. 



ViQUESNELiA, Deshayes, 185Y. 

 Shell internal, nidimentaiy, oval, suborbicular, slightly con 

 cave below, and thickened at the edges ; summit sub -central. 



Fig. 125. Testacella haliotoides, Fer.* 



Testacella, Cuvier. 



Shell small, car-shaped ; situated on the j)Osterior extremity 

 of the body. 



Animal, slug-like, elongated and tapering towards the head ; 

 back with two principal lateral furrows, from which numerous 

 vein -like grooves ramify; mantle not larger than the shell; 

 respiratory orifice on the right side, beneath sub-spiral apex of 

 the shell ; reproductive orifice behind the right tentacle. The 

 Testacella is subterranean in its habits, feeding on earth-worms, 

 and visiting the surface only at night. Its lingual membrane 

 is very large and wide, with about 50 rows of 20.20 teeth, 

 which diminish rapidly in size towards the centre ; each tooth 

 is slender, barbed at the point, and slightly thickened at the 

 l)ase, and furnished with a projection on the middle of the 

 posterior side. 



Fig. 126. t 



l^ui-ing winter and diy weather the Testacella forms a sort 

 of cocoon in the ground by the exudation 

 of its mucus. If this cell is broken, tho 

 animal may be seen completely shrouded 

 in its thin opaque white mantle, which 

 rapidly contracts until it extends but a 

 little way beyond the margin of the shell. 

 Fig, 127 represents T. Maugei (lately 



* Back view of a half-grown individual ; side view of shell on the tail, and front 

 cifcw of the head. From specimens communicated by Ailhur Mackie, Esq^ , of Norwich. 



t Part of the lingual membrane of T. haliotoides, from a preparation by Fisher 

 Cocken, Esq., of Botesdale. The dentitioQ resembles that of lanthina. 



Eig. 127. Testacella. 



