PHYLUM ECHINODERMATA 



403 



The ccelome contains a fluid in which float numerous amcebo- 

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



rod ami 

 rin^ves , 



ri.bl.vee 

 pot vee 

 stom. 

 irU yea 



. gen. op 



. rcujL OSS 

 inteross 



- qen . du- 

 TTLod can 

 int. ves 



^gte?!,.^i. 



CU.V org 



Pig. 329.— Internal organs of a Kolothlirian as seon when the body-wall is divided along 

 the middle of the dorsal surface, h. w. body-wall ; circ. mua. circular layer of muscle ; 

 cl. cloaca ; cL op. cloacal opening ; Cuv. <y)'g. Cuvieran organs ; gen. ap. genital aperture ; 

 ge-a. du. genital duct ; gen. gl. gonad ; int. intestine ; inter, oss. inter-ambulacral ossi- 

 cles ; int. ves. intestinal hsemal strands ; long. mus. longitudinal band of muscle ; viad. can. 

 madreporic canals ; mes. mesentery ; pol. ves. Polian vesicles ; rad. amb. radial ambulacral 

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

 tory trees ; ring-ves. ring-Tessel 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 



