344 



CEYLON PEARL OYSTER REPORT. 



EXPLANATION OF PLATES. 



PLATE 1. 



40. 



Figs. 1 and 2. Pcrophora 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. 



The alimentary canal, x 20. 



Tentacles, dorsal tubercle, languets 



Edeinascidia sluitcri, n. sp. x 2. 



Part of the stolon, x 5. 



The dorsal edge, to show muscles. 



Part of the branchial sac. x 40. 



The tentacles, dorsal tubercle, &c. 



The alimentary canal, x 10. 



Edeinascidia solida, n. sp. Nat. size. 



Part of the branchial sac. x 40. 



The dorsal languets. x 40. 



Edeinascidia thurstoni, Hrdn. Nat. size. 



The largest ascidiozooid a little enlarged. 



The tentacles, x 40. 



The dorsal languets. x 40. 



The gonads, x 20. 



7. 



8. 



9. 

 10. 

 11. 

 12. 

 13. 

 14. 

 15. 

 16. 

 17. 

 18. 

 19. 

 20. 

 21. 

 22. 



xlO. 



x40. 



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



xlO. 

 Figs. 24, 25 and 26. Rhodosoma ccykmicum, 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. Astidia polytrema, 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. Astidia 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. 



x40. 



(Chilaw), with test 



8. Another specimen 

 removed. 



9. Dorsal tubercle of the same, x 40. 

 Figs. 10 to 12. Astidia depressiuscula, Heller, three 



specimens. Nat. size. 

 Fig. 13. With test removed. 



,, 14. Another specimen. 



15. Branchial sac of same, x 40. 

 JMgB. 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. Microcosrnus 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 peripharyngeal bands. 



x40. 

 Part of branchial sac. x 40. 

 Microcosrnus longiiuMs, n. sp. Nat. size. 

 Same, test removed. 

 Part of branchial sac. x 40. 

 Dorsal tubercle, x 40. 

 Iihabdocynthia pallida, Heller. 

 Test removed. 

 Dorsal tubercle. 



Atrial aperture, alimentary canal and left 

 gonads, from inside, slightly enlarged. 



