PHYLUM ECHINODERMATA 



id sends off five radial vessels, as well as dorsal and ventral vessels 

 (int. ves.) accompanying the enteric canal, and a plexus surrounding 

 ' J ie left respiratory tree. 



cross 



radamh 

 ringv&s 



ri.bl.ves 

 pol.ves 

 stom 

 int-ves 



cL.oJb 



. Internal organs of a Holothurian as seen when the body-wall is divided along the 

 middle of the dorsal surface : b. v. body-wall ; circ. mv.s. circular layer of muscle ; cl. cloaca ; 

 cl. op. cloacal opening with five teeth ; Cur. org. Cuvieran organs ; //</(,. </>. genital aperture ; 

 gen. </u. genital duct ; <ien. gl. genital gland ; 'int. intestine; inter, oss. inter-ambulacral ossi- 

 cles ; int. ves. intestinal vessels ; I<H><J. ,,,cx. longitudinal band of muscle ; mad. can. madreporic 

 canals; mes. mesentry ; ,/. ves. I'oliaii vesicles; ,<>. u,,,l,. radial ambulacral vessel; ri. bl. 

 v-.v. ring blood-vessel ; resp. respiratory trees ; ring-res, ring- vessel of the ambulacral system ; 

 stom. stomach. (After Leuckart.) ^ 



The coelome contains a fluid in which float numerous amcebo- 

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

 flattened nucleated corpuscles containing a red colouring matter 



B B 2 





