238 



MANtTAL OF THE MOLLtTSCA. 



ViQUESl^ELiA, Deshayes, 1857. 

 Shell internal, rudimentary, oval, suborbicular, siiglitly con- 

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



Fig. 125. Testacella haliotoides, Fer.* 



Testagella, Cuvier. 



Shell smallj ear-shaped ; situated on the posterior extremity 

 of the body. 



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

 back with two principal lateral farrows, 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 

 base, and furnished with a projection on the middle of the 

 posterior side. 





Fig. 126.t 



During winter and dry weather the Testacella forms a sort 



tn -..:^,^^^ of cocoon in the ground by the exudation 



s ^tt^ m/.^->v 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. 



Eig. 127. Testacella. ^[g^ 127 represents T. Maugei (lately 



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

 view of the head. From specimens communicated by Arthur Mackie, Esq,., of Norwich. 



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

 Cocken, Esq., of Botesdale. The dentition resembles that of Icmtluna. 



