92 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [JuilG 14, 



the Horiiera of M. Lamouroux*, and founded on a recent coral ob- 

 tained by Tilesius on the coast of Kamtchatka. In describing his 

 only species, Horn, frondiculata (Joe. cit. p. 41), M. Lamouroux 

 refers doubtfully to the Millepora lichenoides of Linnaeus f, the 

 Millejwra tuhvpora of Ellis and Solander|:, and Lamarck's Retepora 

 f7'ondicidata% \ but ]\L Milne-Edwards, in his well-known memoir 

 on the genus II, seems to consider the whole three as true synonyms 

 of H. frondiculata. How far Tilesius's coral is really identical with 

 that of Linnaeus, Ellis and Solander, and Lamarck, can be gleaned 

 only from Lamouroux' s figures ; but if they are correct delineations, 

 that authority was apparently justified in marking his references as 

 doubtful. Moreover, it should not be forgotten that Tilesius obtained 

 his zoophyte on the coast of Kamtchatka, while that of Linnceus, &c. 

 exists in the Mediterranean. MM. de Blainville and Milne-Edwards^ 

 having however adopted unqualifiedly the term Horn, frondiculata 

 for the Mediterranean iVscidian polype, it must be considered in this 

 notice as the type of the genus, and as such be the subject of com- 

 parison with the Isle of Wight fossil. The existing as well as the 

 extinct coral is strictly tubular ; in each, those visceral cavities open 

 on only one side of the branch ; each also has subordinate apertures 

 independent of textile pores over the whole surface ; but they are far 

 less numerous in Horn, frondiculata than in the fossil ; and the ex- 

 terior of both is modified by age. Were these agreements considered 

 by themselves, they might be regarded as warranting a generic iden- 

 tity ; but a comparative analysis of each structure will show something 

 more than specific distinctions. 



M. Milne-Edwards' s general figare <d{ Horner a frondiculata (op. 

 cit. pi. 9. fig. 1) represents most completely the peculiarities of 

 growth, or strong main branches with numerous relatively slender 

 side-shoots, the latter presenting a uniformly very small breadth 

 even close to the base of the specimen : a similar character is visible 

 in Ellis and Solander' s figure (Nat. Hist. Zoophytes, pi. 26. fig. 1) ; 

 likewise in that of Esper (Pflanz. Mill. tab. 3), and Pallas (Elenchus, 

 Germ. Trans, tab. 12. fig. 42). They w^re still more prominent in 

 specimens presented to the author by the Rev. W. Hennah, and 

 which will be the chief source of the following remarks. The main 

 branches in the youngest state are slender, and formed almost wholly 

 of tubes ; the large apertures project, particularly on the side of the 



* Exposition Methodique, p. 41. tab. 74. figs. 7, 8, 9. In the description of pi. 26. 

 fig. 1, the coral so dehneated by Elhs and Solander is also called Hornera frondi' 

 culata and without a note of interrogation ; nevertheless, no allusion is made in 

 the body of the work to tiiat figure. See note X infra. 



t Syst. Nat., Edit. x. torn. i. p. 791, 1758. Consult Esper's Pflanzenthiere, 

 Millepora, tab. 3. 



X Natural History of Zoophytes, p. 139. pi. 26. fig. 1, 1786, apud M. Milne-Ed- 

 wards's Memoir on Hornera, infra note H. 



§ Anim. sans Vert. Edit. 1816, toni.ii. p. 182 ; Edit. 1836, ii. p. 277. 



II Annales des Sciences Naturelles, 2nd Series, Zool., torn, ix., 1838, or Re- 

 cherches sur les Polypes, Mem. sur les Crisies, p. 17 e^ seq. 



^ De Blainville, Man. d'Actinol. p. 419 ; Milne-Edwards, 07?. cit., and 2nd Edit. 

 Lamarck, tome ii. p. 277 and note. 



