GENERA OF FA VOSITID^E. 105 



lopora actita, Lam. (see Hist. Nat. des Cor., PI. F 4, fig. 2) ; 

 but I have no means of knowing how far this resemblance may 

 express an actual agreement in anatomical structure, and the 

 former assuredly does not possess the coenenchyma stated to 

 exist in the latter coral. 



As distinguished by Milne-Edwards and Haime (Pol. Foss. 

 des Terr. Pal, pp. 304, 305), Trachypora is separated from 

 Dendropora, Mich., by the fact that the "coenenchyma" (that 

 is, the thickened margin of the calices) is smooth, or almost so, 

 in the latter, whereas in the former it is adorned by irregular 

 vermiculate or sub-echinulate stria;. The genus Rhabdopora 

 E. and H., again, is said to be characterised by having four- 

 sided branches, with an echinulate " coenenchyma," and calices 

 arranged in simple longitudinal series, the septa being very 

 distinct and slightly exsert. Professor Martin Duncan, in his 

 masterly " Third Report on the British Fossil Corals " (Rep. 

 Brit. Assoc, 1872), concludes — as I think, rightly — that the 

 maintenance of a generic distinction between Dendropora, 

 Mich. (1845), and Rhabdopora, E. and H. (185 1), is quite 

 untenable ; but I am unable to follow this distinguished 

 authority in his further conclusion that both of these genera are 

 identical with Seriatopora, Lam., which, in turn, is said to be 

 inseparable from Pocillopora, Lam., the name of Aci'opora, 

 Oken, being rehabilitated for the reception of all of these. 

 Trachypora, E. and H., is, on the other hand, doubtfully 

 referred to the Alcyonaria. The researches of Verrill (Trans. 

 Conn. Acad., vol. i., 1868) have, however, shown that Pocillo- 

 pora is closely related to the Ociilinidce ; and it is highly prob- 

 able that Seriatopora, whether generically separable or not, 

 will ultimately be found to occupy a similar zoological position. 

 Dr Rominger, on the contrary, merges Trachypora under 

 Dendropora, Michelin, holding that the surface-ornamentation 

 is a character of merely superficial importance. In this view I 

 should be quite prepared to concur, if it were once shown that 

 Dendropora explicita, Mich., the type of the genus, possessed 

 the internal structure of Trachypora ; but in the absence of any 



