4X:-;;W;-^-,-, 



Fio. 371.— Organisa- 

 tion of Holothuria 

 tnbulosa. The blood 

 vasculiir system is 

 market! black. 1, Oral 

 tentacles ; '2, stone 

 canals ; 3, ^vater "\-as- 

 cular ring ; 4, Polian 

 vesicle ; 5, ^^onads ; 0, 

 longituiUnal muscles ; 

 7, anterior section of 

 intestine ; S, ventral 

 intestinal vessel ; 9, 

 radial water vessel ; 10, 

 vascular anastomoses ; 

 11, dorsal intestinal 

 vessel ; 12, filaments 

 and strands (of the 

 ^Q nature of both muscle 

 and connective tissue) 

 which attach the cloaca 

 to the body wall ; 13, 

 cloaca ; 14, cloacal 

 aperture (anus) ; 15, 

 middle section of the 

 intestine ; 16, posterior 

 section of the same ; 



17, right branchial tree; 



18, rete mirabile ; 10, 

 radial canal of the 

 water vascular system ; 



20, left branchial tree ; 



21, tentacle ampulla- 

 (after Milne Edwards 

 and Cams). 



