261 



Fig. 3. Fully formed larva; the hydrocoel has formed the primary lobes. The rudimentary 

 skeleton (sk.) is seen, ^^"/i- 



4. Larva in a slightly less advanced stage, with a right hydrocoel. i^»/i. 



5. Fully formed, normal larva. The round hole seen in the stomach is the entrance 

 to the rectum, which is seen here directly from above, i^'/i- 



6. Fully formed larva, in side view. The oral lobe is bent somewhat forwards so as 

 to cover the oral region. 



7. Abnormal larva, ^^"/j. 



8. The young Ophiuran lying within the ovarial sac, on the wall of which are seen 

 two small, nearly absorbed eggs (e.). '"/i- 



9. An ovary, attached to the genital rhachis; a trabecule of connective tissue is pro- 

 ceeding from the ovary, '^/j. 



a. c. anterior coelom; e. egg; h. hydrocoel; m. mouth; n. nerv(?); p. c. posterior 

 coelom; r. rectum; rh. rhachis; sk. skeleton; st. stomach; tr. trabecule. 



Plate XXXIII. 



Fig. 1. Larva of Asterina pectinifera (M. Tr.); 18 days old. Drawn from life. ""/i. 



2. Fully formed larva of same species; same age. Drawn from life. ^°°/i- 



3. Larva of Astropecten scoparius M. Tr., 7 days old. s. c. suboral cavity. *'/i. 



4. Larva of same species, 19 days old. Side view. **/i. 



5. Larva of same species, in metamorphosis. 19 — 21 days old. ^Vi- 



6. Larva of Gymnasteria carinifera (Lamk); 26 days old. ^^"/i. 



7. Bipinnaria sp. from the Red Sea. '%• 



8. Larva of Stichopus californicus (Stimps.), 6 days old. Drawn from life. '^/j. 



9. Larva of same species, same age; side view. Drawn from life. "/i. 



