238 MOUTH AND DIGESTIVE APPARATUS OF CRUSTACEA. 



(Fig. 472). In suctorial Crustacea, on the contrary, the mouth 

 is prolonged into a sort of beak, or trunk, as we have already 

 seen in Insects of the same habits. In the interior of this tube, 

 we find thin and pointed appendages, which perform the office 

 of little lancets ; and on each side we commonly see organs, 

 which are analogous to the auxiliary jaws of masticating 

 Crustacea, but which are so formed as to serve to fix the 

 animal on its prey. 



776. The digestive canal extends from the head to the pos- 

 terior extremity of the abdomen ; and is composed of a very 

 short oesophagus, a large stomach (0, Fig. 466) generally armed 

 interiorly with powerful teeth, of a small intestine, and of a 

 rectum. In some Crustacea, the bile is secreted by biliary 



FIG. 464. ANATOMY OF A CRAB ; the greater part of the carapace having been 

 removed ; p, portion of its lining membrane ; c, heart ; as, ophthalmic artery ; aa, abdo- 

 minal artery ; 6, branchiae in their natural position ; 6', brancbia turned back to show 

 their vessels ; fl, lower portion of the shell ; /, appendage of the foot-jaw ; e, stomach ; 

 m, muscles of the stomach ; fo, liver. 



vessels, like those of Insects ; but in general there is a very 

 voluminous liver, divided into several lobes, and composed of a 



