76 



Islands, brought to France by M. Dupetit Thouars, and hence called 

 FlaheUum Thouarsii, n. 10. t. 8. f. 5, which appears to be distinct 

 from the two former. 



From the examination of the numerous specimens of Flahellum Pa- 

 voninum which I have been enabled to compare and collect, I am in- 

 clined to believe that all the specimens which are brought from the 

 Japanese Seas belong to a smgle species, which I believe will include 

 as varieties the following species described by M. Milne-Edwards and 

 M. Haime, viz.: — 



1. Flahellum distinctum, n. 2. The specimen in the British Mu- 



seum, from which this species is described, came from Japan, 

 and not the Red Sea, as stated in the work cited. 



2. F. debile, n. 23. t. 8. f. 2. 



3. F. Sumatrense, n. 24. 



4. F. spinosum, n. 25. t. 8. f. 4. 



5. F. aculeatum, n. 26. t. 8. f. 3. 



6. F. compressum, n. 20 = Fungia compressa, Lamk. 



7. F. Bairdii, n. 32. From Japan. 



8. F. Cumingii, n. 33. t. 8. f. 11. 



9. F. elonffatum, n. 34. t. 8. f. 7. 



10. F. profundum, n. 35. China (Fortune). F. sphetiiscus, u. 42 ? 



11. F. crassum, n. 36. t. 8. f. 8. 



12. F. crenulatum, n. 37. 



13. F. elegans, n. 38. From Japan ; B. M. 



14. F. Candeanum, n. 39. t. 8. f. 13. 



15. F. Stokesii, n. 40. t. 8. f. 12. 



16. F. Oioenn,n. 41. t. 8. f. 9. 



I thought at first that these specimens might be separated into two, 

 according to the colour, some being red, with the sides of the coral 

 keeled, and others white, with the sides more or less rounded ; Fla- 

 hellum Pavoninum, Lesson, being the type of one species, and Fnngia 

 compressa, of Lamarck, of the other. But there are specimens red on 

 one side and white on the other, and some on the other hand keeled 

 on one edge and rounded on the other ; some with elongated spines 

 on one edge, and spiniferous or only with a slight tubercle on the oppo- 

 site one ; sometimes one edge has two spines and the other only one, 

 or a tubercle, and the extent of the truncation of the base differs in 

 every example. 



The same examination has also induced me to believe that the spe- 

 cimen which these authors have described under the name of Placo- 

 trochus Icevis, p. 283. t. 8. f. 15, is only a variety of the same species ; 

 and that Acanthocyathus Grayii, 293. t. 9. f. 2, is only a specimen of 

 the same, species which has lost its compressed form. I have not 

 seen Rhizotrochus typus, p. 282. t. 8. f. 16, or Blastotrochus nutrix, 

 p. 284. t. 8. f. 14 ; but from the figures, I have great suspicions that 

 they are only modifications of the same species. 



To give some idea of the variations produced by local causes in 

 corals, I may state that the specimens which Messrs. Milne-Edwards 

 and Haime have described under the generic name o( Heterocyathus, 

 are only specimens of the genus Cyaihus which have been changed 



