106 



THEEE CRUISES OF TIIK 'BLAKE. 



while the structure o the ambulacral furrow approaches that 

 of the Comatulae. Hynienodiscus and Brisinga thus form 





Fig. 383. Hymenodiscus Agassizii. 1-5.. (Perrier.) 



among starfishes a very peculiar family, marked by most excep- 

 tional characters. The study of Hymenodiscus, closely allied 



Fig. 384. f-. Fig. 385. Magnified spine. 



Hymenodiscus Agassizii. (Perrier.) 



to the northern Brisinga, has had an important bearing on the 

 morphology of the starfish skeleton. 



