406 PERCY SLADEN TRUST EXPEDITION 



EXPLANATION OF PLATES. 



Plate 23. 



Zoanthidea. 



Fig. 1. Larva I, Zoanthina diamanta, n.sp. : (a) side view ; (6) oral surface. 



Fig. 2. Transverse section of larva I, across aboral part. 



Fig. 3. Larva II, Zoanthina variabilis, n.sp. : (a) side view ; (6) oral surface. 



Fig. 4. Transverse section of larva II, across aboral part. 



Fig. 5. Larva III, Zoanthina sladeni, n.sp.: (a) side view; (b) oral surface. 



Fig. 6. Transverse section of larva III showing the endodermal swellings and their attachment 



to the mesenteries. 

 Fig. 7. Larva IV, Zoanthina gardineri, n.sp.: (a) side view; (6) oral surface; (c) aboral surface. 

 Figs. 8 — 12. Transverse sections of larva IV, showing the mesenteries and mesenterial filaments, 



series drawn near the enterostome. 



Plate 24. 



Gerianthidea. 



Fig. 13. Larva I, Dactylactis cerfensis, n.sp.: (a) side view; (b) oral surface. 

 Fig. 14. Larva II, Ovactis super ficialis, n.sp.: (a) side view; (6) oral surface. 

 Fig. 15. Larva III, Ovactis indiana, n.sp.: (a) side view; (6) oral surface. 



Heooactiniaria. 



(1) Larvae with 8 mesenteries. 



Fig. 16. Larva I: (a) side view; (b) oral surface. 



Fig. 17. Larva II : (a) side view ; (b) oral surface. 



Fig. 18. Transverse section of larva II showing reflexed free edge of stomodseum within 



mesenterial chambers. 

 Fig. 19. Transverse section of larva II showing the convoluted mesenterial filaments, the loose 



endodermal tissue within the coelenteron, the largest embryo cut longitudinally and 



a second embryo. 



(2) Larvae with 12 mesenteries. 



Fig. 20. Larva I : (a) side view ; (b) oral surface. 

 Fig. 21. Larva II : (a) side view ; (b) oral surface. 



Fig. 22. Transverse section of part of the wall of the column of larva III and a mesentery 

 expanded at its free edge in which are spherical bodies. 



(3) Larva with 20 mesenteries. 



Fig. 23. Larva : (a) side view ; (b) oral surface. 



