CLASSIFICATORY POCIIION OF SOME MADREPORAKIA . 129 



Genus Heterogyra, Eeuss. 



The comparatively circular corallites free at the margin, and the 

 increase both by gemmation and by irregular serial growth, distin- 

 guish this genus from its close ally Latimceandra. It differs from 

 Choinsastrcea, as shown in the definition given by its founder. 



Genus Stmphyllia, Ed. & H. 



After due consideration and careful examination of the recent 

 species of Sympliiillia, I restore Symphyllia Etheridgei^ nobis, which 

 had been removed to a new genus, PJii/Uofjyra, by Mr. Tomes. It is 

 usual, when a naturalist alters the generic position of a species, that 

 a reason should be given ; this was not done by Mr. Tomes, who 

 created a genus to include the SymjjJiyllia just alluded to. 



No comparison of the new genus Phyllogyra, Tomes, with Sym- 

 phyllia was instituted, and yet a little study of the figures given 

 (pi. vi. figs. 6 and 7, Pal. Soc. 1872, Monogr. Brit. Foss. Corals, 

 pt. iii.), and their comparison with calicos of recent Sympliyllice, 

 will show that the fossil and recent species are generically allied. 

 This subject has been considered in the " Revision of the Genera," 

 p. 92, and although I had grave doubts about the genus Pliyllogyra, 

 Tomes, I placed it in the classification. But I differ from the author 

 of the genus in believing that the calicos he thinks came from gemma- 

 tion are the result of fissiparity. The genus is not synonymous with 

 Symphyllia. It is very interesting to note the similarity of the figure 

 given of the base of Phyllogyra, Tomes, op. cit. pi. sviii. fig. 5, and 

 that of Phylloseris riigosa, Tomes, fig. 8 of the same plate. 



Thecoseris polymorpha, Tomes, was described in the Geological 

 Magazine ; but, although it is figured in the essay on the Madreporaria 

 of the Lower Oolite (pi. xviii. figs. 12, 13), no description of the 

 species is given in the text. This is to be regretted, because the 

 genus cannot have any alliance with the Australian form which I 

 described some years since, or with a well-known Lower Cre- 

 taceous and Tertiary genus named by me Tiirhinoseris. Mr. Tomes 

 clearly would have Turhinoseris and Palceoseris, nobis, made syno- 

 nymous with Thecoseris, E. de From. But the anatomy of the series 

 of forms shows marked distinctions between the genera. As a 

 matter of fact, Pratz has shown that Leptophyllia, Eeuss, is a Fungid 

 with perforate septa, and Haplarcea, Milasch., is synonymous. Xow 

 Thecoseris only differs from Leptophijllia in having a strong epitheca, 

 a subgeneric attribute. Thus Thecoseris is a subgenus, and may or 

 may not be used according to the value pala3ontologists put on sub- 

 genera, and it is long after Leptophyllia in date of publication. 

 Turhinoseris has solid septa and belongs to a different family of the 

 Fungida from Leptophyllia and ThecoseHs. In the " Revision of the 

 Genera " I have shown that it is associated with Trochoseris and 

 other allied genera. Palceoseris I have reduced to the position of a 

 subgenus ; its distinction from Turhinoseris is subgeneric. 



Thecoseris polymorpha, Tomes, should remain where its author 

 placed it, but onlv as a subgenus of Leptophyllia, Eeuss. The form 

 Q. J. G. S. T^o.^ieS. K 



