298 COMPARATIVE ANATOMY chap. 



Fani. 1. Linckiidae : Chaetaskr, Ophidiadcr, Linckia, Metrodira, etc. Fain. '2. 



Vui. 242.— Hymenaster caelatus (ut'tir Sladen), witli arms bent back. 



Zoroasteridse : Zoroaster, Cncmidostcr (Fig. 241). Fam. 3. Stichasteridse : Sti- 

 chastcr, etc. Fam. 4. Solasteridse : SoJaster, Crossaskr, Corcthrastcr, etc. Fam. 5. 



Fui. 243.— Hymenaster nobilis (alter Sladen), from tlie oral side, ; natural size. 



Pterasteridse, with brood cavity on the apical side of the disc : Pteraster, Retastcr, 

 Hiiiiicnustcr (Figs. 242 and 243), Myxaslcr, Hcnthuster, Pylhonaster, etc. Fam. 6. 



