ECHINODERMATA. 



155 



valves and were apparently dead : nevertheless there was nothing 

 to lead to the supposition that only dead shell-fishes were attacked, 

 so that it is difficult to imagine how the delicate vesicles above de- 

 scribed escaped injury from the closing of the valves. M. Deslong- 

 champs thinks that probably the Asterias pours into the shell a 

 torpifying secretion, and thus ensures the death of its victim. 



(195.) The absorption of the nutritious portions of the food in 

 the Echinodermata is entirely accomplished by the veins distributed 

 upon the coats of the digestive cavities, so that the chyle resulting 

 from digestion is at once introduced into the vessels appropriated 

 to circulation. 



In Asterias, the intestinal veins form a fine vascular network, 

 covering the stomach and the ten digestive caeca. The venous 

 trunks derived from all these sources unite to form a circular 

 vessel (Jig. 67, e), which likewise receives branches derived from 

 the ovaria and other sources. 



The circular vein thus formed, which seems to be the common 

 trunk of the venous system, communicates with another vas- 

 cular circle placed around the mouth (s), by means of a dilated 



