286 



COMPARA TI VE ANA TOMY 



Fig. 224.— Pelagothuria natatrix (after Ludwig), completed ; from above. 1, Body ; 2, auus. 



Fig. 225.— Pelagothuria natatrix (after Ludwig) ; front view, i.e. from the oral pole. 1, Mouth : 

 2, oral tentacles : 3, disc ; 4, canals of the disc. 



