958 



CRUSTACEA 



a proboscis-like projection, at the extremity of which is the narrow 

 orifice of the mouth, which draws in the semi-fluid aliment. Instead 

 of being furnished (as in the higher crustaceans) with two pairs of 

 antenna? and numerous pairs of ' foot-jaws,' it has but a single pair 

 of either ; it also bears four minute ocelli, or rudimentary eyes, set 

 at a little distance from each other on a sort of tubercle. From 

 the thorax proceed four pairs of legs, each composed of several joints, 

 and terminated by a hooked claw ; and by these members the 

 animal drags itself slowly along, instead of walking actively upon 

 them like a crab. The mouth leads to a very narrow oesophagus 

 (a), which passes back to the central stomach (b) situated in the 



FIG. 719. Anvmothea pycnogonoides : a, narrow oesophagus ; 

 b, stomach ; c, intestine ; (I, digestive Cffica of the foot-jaws ; 

 e, e, digestive c-eca of the legs. 



midst of the thorax, from the hinder end of which a narrow intes- 

 tine (c) passes off. to terminate at the posterior extremity of the 

 body. From the central stomach five pairs of c;t j cal prolongations 

 radiate, one pair (d) entering the foot-jaws, the other four (e, e) 

 penetrating the legs, and passing along them as far as the last joint 

 but one ; and those extensions are covered with a layer of brownish- 

 yellow granules, which are probably to be regarded as a digestive 

 gland. The stomach and its ca?cal prolongations are continually 

 executing peristaltic movements of a very curious kind ; for they 

 contract and dilate with an irregular alternation, so that a flux and 

 reflux of their contents is constantly taking place between the 

 central portion and its radiating extensions. The perivisceral space 

 I>H ween the widely extended stomach and the walls of the body and 



