140 



MANUAL OF ZOOLOGY. 



Besides the spines, which are sometimes of a very great 

 length, the test often bears curious little appendages, called 

 " pedicellariae," and often supposed to be parasitic. Each of 



Fig- 37- Morphology of Echinoidea. i. Portion of the test of Gnlerites hemis- 

 phericus enlarged, showing an inter - ambulacra! area (a), and an ambulacral 

 area (b). 2. Galerites hemisphericus viewed from above, a Inter-ambulacra; b 

 Ambulacra. 3. Genital and ocular disc of Hetnicidaris intermedia, enlarged, c 

 Ocular plate ; d Genital plate ; e Anal aperture ; f Madreporifprm tubercle. 4. 

 Spine of the same. (After Forbes.) The tubercles are mostly omitted on figs. 2 and 

 3 for the sake of clearness. 



these consists of a stem, bearing two or three blades or claws, 

 which snap together and close upon foreign objects, like the 



Fig. 38. Cidaris papillata. (After Gosse.) 



beak of a bird. Their action appears to be independent of 

 the will of the animal, and their true function is not known. 



