298 COMPARATIVE ANATOMY CHAP. 



Fam. 1. Linckiidse : Chactnsfe r, OpMdiaster, Linckin, Metrodira, etc. Fam. '2. 



FIG. -24-2. Hymenaster caelatus (after Sladen), with arms bent back. 



Zoroasteridae : Zoroaster, Cncmidastcr (Fig. 241). Fam. 3. Stichasteridse : Sti- 

 i; etc. Fam. -4. Solasteridse : Sof aster, C'rossastcr, Corftkrastrr, etc. Fam. 5. 



Fie. -_'4o. Hymenaster nobilis (al'ter Sladen), t'nuu the mal side, v natural :<ize. 



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

 Ifi/nii-iKiftfcr (Figs. 242 and 243), Myxastct; Bi'nthastrr, Pi/thonastcr, etc. Fam. 6. 



