IX 



PHYLUM ECHINODERMATA 



403 



The ccelome contains a fluid in which float numerous amcebo- 

 cytes, similar to those of the Starfish, and also a number of 



radainh 



ri.bl.vcs 



pol. ves 



s torn 

 intv&s 



ci.rc 



res 



cciv org 



cl 



Cl.oj} 



Fin. 329. Internal organs of a Holothurian as scon when the body-wall is divided along 

 the middle of the dorsal surface. 6. w. body-wall ; circ. mus. circular layer of muscle ; 

 cl. cloaca ; cl. op. cloacal opening ; Cuv. org. Cuvieran organs ; gen. ap. genital aperture ; 

 gen. du. genital duct ; gen. gl. gonad ; int. intestine ; inter, oss. inter-ambulacra! ossi- 

 cles ; int. ves. intestinal haemal strands ; long. mus. longitudinal band of muscle ; mad. can. 

 madreporic canals ; mes. mesentery ; pol. ves. Poliau vesicles ; rad. ami), radial ambulacral 

 vessel ; rad. oss. ambulacral ossicles ; ri. bl. ves. ring strand of haemal system ; resp. respira- 

 tory trees ; ring-ves. ring-vessel of the ambulacral system ; stom. stomach. (After Leuckart.) 



flattened nucleated corpuscles containing a red colouring matter 

 -haemoglobin almost identical with that which gives the red 

 colour to the blood of the higher animals. 



D D 2 



