166 



MANUAL OF ZOOLOGY 



SECT. 



Accompanying the madreporic canal there is an organ 

 the ovoid gland the relationships and function of which have 

 given rise to a considerable amount of difference of opinion. 

 It is a fusiform body, the interior of which is divided up 

 into a number of freely-communicating spaces. 



The Starfish is unisexual, each individual possessing 



FIG. 84. Ambulacral system of a Starfish, a. ampullae ; ap. Polian vesicles 

 (hollow appendages of the ring-vessel not present in Asterias) \ c. circular 

 canal ; tn. madreporite ; ;;/'. madreporic canal ; p. tube-feet ; r. radial vessels ; 

 r f . branches to ampullae. (After Gegenbaur.) 



either ovaries (Fig. 82, A, Ovy.} or fesfes, which appear very 

 similar until they are examined microscopically. They 

 consist of masses of rounded follicles, like bunches of 

 minute grapes, a pair in each inter-radial interval. The 

 ducts, by means of which the ova or sperms, reach the 



