344 



CEYLON PEARL OYSTER REPORT. 



EXPLANATION OF PLATES. 



PLATE 1. 



Figs. 1 and 2. Perophora hornelli, n. sp. Nat. size. 



Fig. 3. Part of the stolon, x 40. 

 Figs. 4 and 5. Parts of the branchial sac. x 40. 



Fig. 6. The atrial aperture, from the inside, x 40. 



7. The alimentary canal, x 20. 



8. Tentacles, dorsal tubercle, languets. x 40. 



9. Ecteinasddia sluiteri, n. sp. x 2. 



10. Part of the stolon, x 5. 



11. The dorsal edge, to show muscles, x 10. 



,, 12. Part of the branchial sac. x 40. 



13. The tentacles, dorsal tubercle, &c. x 40. 



14. The alimentary canal, x 10. 



15. Ecteinasddia solida, n. sp. Nat. size. 



16. Part of the branchial sac. x 40. 



17. The dorsal languets. x 40. 



18. Ecteinasddia thurstoni, HRDN. Nat. size. 



19. The largest ascidiozooid a little enlarged. 



20. The tentacles, x 40. 



21. The dorsal languets. x 40. 



22. The gonads. x 20. 



Fig. 23. Branchial and atrial siphons, from interior. 



xlO. 

 Figs. 24, 25 and 26. Rhodosoma ceylonicum, n. sp. 



Nat. size. 



Fig. 27. Anterior end opened to show siphons. 

 28. The short lateral muscle bundles. 

 29. The branchial siphon and tentacles, x 40. 

 30. The branchial sac. x 40. 

 31. Connecting ducts and imperfect bars. 



x300. 



32. The dorsal languets. x 40. 

 ,, 33. The dorsal tubercle, x 40. 

 34. Ascidia polytrenia, n. sp. Nat. size. 

 ,, 35. Dorsal tubercle and neighbouring parts. 



x40. 



36. Transverse muscles of the mantle, x 40. 

 37. The branchial sac. x 40. 

 38. Ascidia mikrenterica, SLUIT., the alimentary 



canal, x 3. 

 , 39. Part of the branchial sac. x 40. 



PLATE II. 



Fig. 1. Ascidia donnani, n. sp. Nat. size. 

 Figs. 2 and 3. With the test removed, from right 

 and left sides. 



The dorsal tubercle, x 40. 



The branchial sac. x 40. 



The dorsal lamina, x 40. 



The muscles of the mantle. 



Fig. 4. 

 5. 

 6. 



7. 

 , 8. 



x40. 

 (Chilaw), with test 



Another specimen 



removed. 



9. Dorsal tubercle of the same, x 40. 

 Figs. 10 to 12. Ascidia depressiitscula, HELLER, three 



specimens. Nat. size. 

 Fig. 13. With test removed. 

 14. Another specimen. 

 ,, 15. Branchial sac of same, x 40. 

 Figs. 16 and 17. Other parts of branchial sac. x 40. 

 Fig. 18. Dorsal lamina, x 40. 

 Figs. 19 and 20. Two dorsal tubercles, x 40. 

 Fig. 21. Tentacles, x 40. 



Fig. 22. 

 Figs. 23 

 Fig. 25. 



26. 



27. 



28. 



,, 29. 



30. 



31. 



32. 



33. 



34. 



35. 



36. 



37. 



38. 



, 39. 



Alimentary canal, enlarged, 

 and 24. Microcosmus manaarensis, n. sp. 

 Same opened, to show hairs of test. 

 Showing the test free inside sandy coat. 

 Atrial aperture, from inside. 

 Test removed. 

 Part of a tentacle. 

 Dorsal tubercle and periphavyngeal bands. 



x40. 



Part of branchial sac. x 40. 

 Microcosmus longitubis, n. sp. Nat. size. 

 Same, test removed. 

 Part of branchial sac. x 40. 

 Dorsal tubercle, x 40. 

 lihabdocynthia pallida, HELLER. 

 Test removed. 

 Dorsal tubercle. 



Atrial aperture, alimentary canal and left 

 gonads, from inside, slightly enlarged. 



