via EGHINODEBMATATHE CCELOMIO VAVITIK* 443 



In certain C'lypeastroida (J-Jc/u'nntfitti'i/s hit'ori*, l'< ro i>,/Ja orbiculnris] small inter- 

 radial, thin-walled, vesicular outgrowths of the lantern membrane, on the base of 

 the lantern itself, have been called Stewart's organs. Two of these orvur in each 



Kn.. ;;,-(]. Viscera of Asthenosoma (a ft IT F. ami P. Sarasin). 1, Gonads ; J. cuii>ti n.-rimi in a 

 Stewart's organ ; 3, Stewart's organ ; 4, muscle lamellie ; 5, radial canal of tin- wati-r vascular 

 sy~u-in; 6, tip of a Stewart's organ; 7, forked radius of the masticatory iVaiin-wnrk ; s and 

 '.i. upper and luwi-i' coils of the intestine ; 10, Polian vesicle ; 11, intestine. 



interradius, but are generally wanting in that interradius in which the intestine in 

 ascending lies upon the lantern. 



3. Ophiuroidea. Two circular membranes, one above the other, 

 found round the oesophagus, and traversing the body cavity, connect 

 the (esophagus with the oral skeleton. They thus cut oft' two very 

 small perioesophageal sinuses from the general body cavity. 



