CARNIVOROUS GASTEROPODS, 813 



slug, and, in lieu of a shield confined to a limited portion of 

 the neck, the whole hody is encased with a thick coria- 

 ceous coat, to guard from the additional pressure to which 

 it is exposed, and to afford sufficient strength to exe- 

 cute its furrows. But the most marked differences are 

 found in the digestive organs. In the mouth there is 

 no corneous denticulated jaw, nor a memhranous spinige- 

 rous tongue ; hut from hetween two vertical lips issues 

 a very small cylindrical proboscis, and appropriated to it a 

 muscle which forms the most curious part in the struc- 

 ture of the creature. It is large, cylindrical, lies along 

 the whole belly, and is attached to the left side of the 

 back by a dozen of very distinct fleshy sli^js, almost perpen- 

 dicular to the principal muscle of the body.* The size and 

 strength of this muscle indicate its paramount importance ; 

 and its actions are of a twofold nature. When the Testa- 

 cellus has become aware of the presence of a prey, to sur- 

 prise and take it unawares is necessary, for the earthworm 

 when alarmed is more alert by far than its foe. The advan- 

 tage is given to the latter by having the power, through the 

 medium of this muscle, of suddenly darting out the pro- 

 boscis, which in an instant is projected and applied to the 

 object in \dew. It is then retracted by the same muscular 

 apparatus, and made simultaneously to grasj) with firmness 

 the struggling \dctims of its ferocity. Mr. G. B. Sowerby, 

 in reference to Testacellus scutulum, says he was surprised 

 " that an animal generally so extremely sluggish in its mo- 

 tions, after discovering its prey by means of its tentacula, 

 thrusting from its large mouth its white, crenulated, revo- 

 lute tongue, should instantly seize upon, with extraordinary 

 rapidity, and firmly retain, an earthworm of much greater 

 size and apparent force than itself; but which, by its utmost 

 exertion, is unable to escape." To increase its power of re- 

 taining a secure hold, the tongue is furnished, around and 

 just beneath (if not upon) its margin, on the outside, with 

 short hair-like bristles. -j- 



The carnivorous Vitrina (Helicolimax lamarckii of Fe- 

 russac) differs from our native species in some respects ; but, 

 according to the Rev. Mr. Lowe, to whom we owe our ac- 

 quaintance with its habits, "is so closely allied, that it 

 would be very rash at present to separate it" from the 

 genus. ;J; When leaves and other vegetable matters were 



* Cuv. Mem. xii. 7. t Mag Nat. Hist. vii. 227 and 414. 



X This opinion of Mr. Lowe's is confirmed by the anatomy of tlie species, 

 excellently developed by the Rev. M. J. Berkeley, Zool. Journ. No. xix. 

 p. 305. 



