486 
E. W. MACE RIDE. 
Fig. 10. — Larva 18 days old viewed from the dorsal surface. X 75. 
ien. Primary tentacles of the water-vasciilar system. 
Fig. 11. — Larva 22 days old just about to metamorphose viewed 
from the ventral surface. X 75. acl.sp. Spines of adult, rac. Yacuity 
in the weh of skin connecting the post-oral arms. 
Fig. 12. — Central portion of a larva 20 days viewed from the dorsal 
surface. X 125. o6.^. Rudiments of plates belonging to the aboral 
surface of the adult. 1. a. c. Left anterior coelom. 1. h. Larval brain. 
1. p. c. Left posterior coelom, r. a. c. Right anterior coelom, r. p. c. 
Right posterior coelom. 
Fig. 13. — Central portion of a larva 20 days old viewed from the 
ventral surface. X 125. int. Larval intestine, vac. A^acuity in the 
web of skin connecting the post-oral arms. 
Fig. 16. — Oral view of a just metamorphosed imago, x 125. a.m. 
Adult mouth, ci. sp. Clavate spines, dent. Tooth. 1. a. Stumps of 
larval arms. o. J. Remnant of oral lobe of larva. 
Fig. 17. — Oral view of imago which has lived for some days after 
Fig. 18. — Aboral view j the metamorphosis. X 125. sph. Sphseridum- 
Fig. 14. — Dorsal view 
Fig. 15. — Yentral view 
of the central portion of a larva of 23 days 
about to metamorphose. X 125. ad. sp. 
Spines of the adult. 
