CHAPTER VIII 



THE FOOD OF ANIMALS NEMERTINES AND 

 CARNIVOROUS MOLLUSCS 



Having briefly dealt with Vertebrates, we now proceed to the 

 consideration of the food and feeding habits of carnivorous Inver- 

 tebrates, beginning with NEMERTINES, and taking next the great 

 phylum of MOLLUSCA. 



NEMERTINES 



These curious worm-like marine forms, which have been de- 

 scribed elsewhere as regards their structure (see vol. i p. 306), 

 are purely carnivorous, preying upon all sorts 

 of creatures, both alive and dead. The mouth 

 and front part of the digestive tube are capable 

 of a large amount of dilatation, enabling com- 

 paratively large bodies to be swallowed with 

 ease. The most remarkable peculiarity of these 

 animals is the possession of a long tubular 

 ' ' proboscis ", which, when not in use, is con- 

 tained in a sheath running along the upper 

 side of the body, from which it can be shot out 

 with great rapidity through a small hole situ- 

 ated in most cases in front of the mouth, though 

 sometimes placed within it. The proboscis 

 appears to be used for seizing food, and in a 

 large number of forms its tip is provided with 

 a sharp stylet, at the base of which poison- 

 glands open (fig. 375). This is probably to 

 be regarded as a means of overpowering 

 prey. 



hd. 



Fig. 375. Front End of 

 Nemertine, with proboscis 

 partly protruded. Seen from 

 above (diagrammatic) 



hd, Head ; pr, proboscis ; 

 st, stylet ; r.st, one of the 

 two sacs containing reserve 

 stylets; p.gl., poison-gland; 

 r. m. , retractor muscle. 



