Testacellus sciitulum Sowerby. 227 



course of about a quarter of an hour, excited the slug to pro- 

 ject the peculiar organ noted. By observing this organ as 

 accurately as I could during the slug's brief exposures of it, 

 and by cutting open the one dead slug, I satisfied myself, in a 

 good degree, that this organ is white, horny, of the figure of 

 the longitudinal half of a hollow cone, with the hollow up- 

 Avards (so as to resemble a deep spoon), and that the slug, 

 when informed of a worm's presence by the contact of its own 

 head with a worm's body, projects this organ under the worm, 

 to the flesh of which it adheres by a tenacious viscum, and 

 perhaps, also, as the organ is hollow, by the aid of suction. 

 It is projected and applied in an instant, and when applied, 

 the action of a muscular structure, connected with its origin, 

 draws it, and with it the worm, into the slug's mouth. The 

 skin and parts of the head of the slug are then gradually 

 turned in, as one would turn in the finger of a glove, or in 

 the manner shown in Mr. Lukis's figure {Jig, 39. c), Mr. Blair 

 informs us, in VI. 43., that the T. scutulum swallows worms 

 (and occasionally a small slug) whole, and the introversive 

 process mentioned (although the testacellus may not be able 

 to employ introversively any very considerable portion of the 

 upper part of its body) must avail it in swallowing worms 

 which it happens to catch by either extremity. Mr. Blair has, 

 however, seen (VI. 43.) " one firmly fixed to the middle of a 

 large worm, the head of the slug being so buried in it that it 

 appeared to be nearly cut in two." In the worm that had, as 

 I have observed above, twisted itself out of the slug's mouth, 

 I noticed, after it had twisted itself out, a piece of its flesh 

 absent close beside the tip of the front extremity, and blood 

 apparent there; and this, as I had not observed any defect in 

 the worm when I applied it to the slug, I take to have been 

 bitten out by the slug. This assumed fact, that quoted before 

 it from Mr. Blair, and the likelihood that it is impracticable 

 for the testacellus, whose body is somewhat slender, to swal- 

 low a large worm doubled, suggest that, although this slug 

 may usually swallow earthworms, &c., whole, it occasionally, 

 also, partakes of the earthworms piecemeal. 



Mr. Blair thinks (VI. 44.) that the Testacellus usually gets 

 hold of the worms underground. However this may be, the 

 animal seems to insinuate its head and neck easily, and not 

 very slowly, into loose broken soil ; and the slender attenuated 

 form of the body, when extended, is not unfavourable to 

 Mr. Blair's idea ; and as the orifice, in the Testacellus, for the 

 admission of air, is at the posterior extremity, just under 

 the outward edge of the shell, protected, as it were, by the 

 eaves of the shell, fancy may imagine the shell designed to 



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