12 JOSEPH A. OLUBB. 



m. f. mesenterial filaments, 

 mg. mesogloea. 

 m. 1. muscle lamellae, 

 oe. oesophagus, 

 oe. in. oesophageal invagination of embryo, 

 ov. ova. 

 p. psendoacroragus. 

 p. b. m. parieto-basilar muscle. 

 s. siphonoglyphe. 

 sph. sphincter. 



t. tentacle. 

 tes. testis. 

 V. verrucaj. 

 X. zooanthellse. 



PLATE I. 



Fig. 1. Farantheopsis cruentata (Couthouy). — Eadial section of the upper part of the body-wall, passing 



through a psendoacroragus. 

 Fig. 2. Paraetis polaris, sp. n. — Drawing of the specimen (natural size). 

 Fig. 3. P. polaris. — Radial section of upper part of body-wall and sphincter muscle. 

 Fig. 4. P. polaris. — Portion of sphincter muscle more highly magnified. 

 Fig. 5. P. polaris. — Horizontal section through the body-wall and mesenteries in connection with 



oesophagus. 

 Fig. 6. P. polaris. — Transverse section of the wall of a tentacte. 



PLATE II. 



Fig. 7. Paraetis papaver (Drayton). — Eadial section through the upper part of the body-wall and sphincter 



muscle. 

 Fig. 8. P. papaver. — Transverse section of wall of a tentacle. 

 Fig. 9. P. papaver. — Section through ovary. 

 Fig. 10. P. papaver. — Section of mesenterial filament. 

 Fig. 11. P. papaver. — Section through portion of a mesentery. 

 Fig. 12. Cystiaetis antaretica, sp. n. — Drawing of specimen (natural size). 

 Fig. 13. C. antaretica. — Section of upper part of body-wall, passing through sphincter muscle. 

 Fig. 14. C. antaretica. — Horizontal section through body-wall and mesentery, with ovary. 

 Fig. 15. C. antaretica. — Section of ovary more highly magnified. 



PLATE III. 



Fig. 16. Grilrina octoradiata (Carlgren). — Eadial section through upper part of body-wall, sphincter and 



opening to ' brood ' chamber. 

 Fig. 17. C. octoradiata. — Section through wall of a tentacle. 

 Fig. 18. C. octoradiata. — Horizontal section through body-wall and mesenteries, including the directive 



mesenteries. 

 Fig. 19. G. hermaphroditiea (Carlgren). — Horizontal section through body-wall and fertile mesenteries. 

 Fig. 20. C. hermaphroditiea. — Section, more highly magnified, of genital gland. 

 Fig. 21. C. hermaphroditiea. — Section through wall of tentacle. 

 Fig. 22. Rhodaetinia erassicornis (0. F. Miiller). — Eeproduction from a photograph of a living specimen, 



illustrating an extreme reduction of the size of the tentacles. 

 Fig. 28. R. erassicornis. — Eadial section through the sphincter of a ' Discovery ' specimen. 



