1 20 PEO"F. P. M. DUlSrCAN ON THE STETTCTUEE AITI) 



and the fourth is, in places, rudimentary ; but in the description 

 of the species it is a fifth cycle that is rudimentary. 



An essay " On the Madreporaria of the Inferior Oolite of the 

 neighbourhood of Cheltenham and Gloucester " appeared in the 

 Journal of this Society in 1882 (Quart. Journ. Geol. Soc. vol. xxxviii. 

 p. 409). I might almost have contented myself with directing the 

 attention of the Society to the reply I made at the close of the 

 reading of this communication ; but unfortunately its author per- 

 sisted for a long time in maintaining what was shown to be an 

 error, and about which there is now no second opinion, namely, the 

 classification of Thamnastrcea in the section Porosa. The whole 

 of the subject has been noticed in the " Revision of the Genera," 

 p. 136. 



Any naturalist who is desirous of advancing the scientific know- 

 ledge of fossils by a philosophical criticism should be well acquainted 

 with the standard work of Milne-Edwards and Jules Haime (Hist. 

 Nat. des Corall.) ; but this work seems not to have been familiar 

 to M.T. Tomes, for he makes a strange error in the course of his 

 criticisms in reference to their work on the group of the Tham- 

 nastrceoe. The genera or subgenera 8ynastr<xa and Gentrastroea (he 

 writes) were proposed by M. de Fromentel (p. 435) ; but the first 

 was a creation of Milne-Edwards and the last of d'Orbigny. 

 M. Milaschewitsch described species of Astrceomorpha, Eeuss, from 

 Nattheim, and although none have been found in England, Mr. 

 Tomes remarked that it corresponds with Centrastrcea^ which is a 

 Thamnastrcea with a styliform columella. ]^ow there were few 

 abler observers than Eeuss, and he would have been the last to 

 have confused Astrceomorpha and Centrastrcea. Pratz * has shown 

 that M. Milaschewitsch was mistaken, and that Astrceomorpha is 

 not an Oolitic but a Triassic genus, and has distinguished it from 

 Gentrastrcea, and, indeed, Eeuss did the same. It is necessary to 

 place Astrceomorpha and Thamnastrcea, with its subgenera, in 

 diff'erent alliances (this subject is more fully considered in the 

 " Eevision of the Genera," &c. p. 135). 



Several species of Oroseris were described with much care in the 

 essay under consideration ; but it is impossible to agree with the 

 author's views of the genus. The sentence in which the author 

 indicates his opposition to the views of Milne-Edwards and Jules 

 Haime, d'Orbigny, Eeuss, and myself, and in which he not only 

 separates Oroseris from Gomoseris most definitely, but also allies 

 it with a genus which he places in the Perforata, shows that he 

 does not study with the aid of that systematic morphology which 

 we owe to the great French zoophytologists. 



In this instance the author even opposes M. de Eromentel, who 

 places the two genera close together, and not amongst the Perforate 

 corals. The following is the quotation (E. E. Tomes, op. cit. 

 p. 440) :— " Genus Oroseris, Edw. & Haime. This genus was 

 associated by its original describers with the genus Gomoseris, to 



* E. Pratz, Palasoiitographica, 1882, p. 103, et seq. 



