406 ME. E. P. TOMES ON [Aug. I903, 



The figures of St. Cassian corals given by Laube l have every 

 appearance of truthful delineation, and several of the species 

 have been determined as British. An examination of the figures 

 of Isastrcea Gumbeli and I. Hauri has led me to conclude that 

 the former represents a true Isastrcea, and the latter a species 

 of Heterastrcea. From the former the present species differs 

 generically, and from the latter specifically in having much smaller 

 calices. 



I avail myself of the present opportunity of adding a few remarks 

 on some other Madreporaria from the Rhaetic formation and from 

 the basement-beds of the Lower Lias. The genus Cyathocoenia was 

 established by Duncan 2 for some species from the Sutton Stone of 

 Glamorgan, and was identified by me in 1884 3 as generically 

 identical with the coral described and figured by Laube as PhylJo- 

 coenia decipiens from the Triassic deposits of St. Cassian. Subse- 

 quently, but during the same year, 4 Duncan made Laube's species 

 the type of a new genus to which he gave the name oiKoilocoenia, 

 under the impression that the corallites were surrounded by a second 

 or outer wall. There is not, however, any second wall, but only a 

 break in the costae connecting the corallites ; yet this is by no 

 means a constant character. In the absence of a second wall, there 

 is nothing to distinguish Koilocoenia from Cyathocoenia. 



It has always been my opinion that the Sutton Stone, containing 

 Rhaetic Madreporaria, should be classed as Rhaetic ; indeed, I believe 

 that the above-named deposit is really Upper Rhaetic. 



Postsceipt. 



[After repeated and protracted search for corals in the Sutton 

 Stone of Glamorgan I have concluded that certain species from that 

 district obtained by myself were undoubtedly Rhaetic, and I 

 recorded them as such in vol. xl (1884), at pp. 357-60, of this 

 Journal, to which I now refer. I may, however, add that the species 

 to which I especially refer are the following : — 



Montlivaltia perlonga, Laube. 

 Thecosmilia rugosa, Laube. 

 Cladophyllia sables vis, Laube. 



Fischeri, Laube. 

 C'alamophyllia cassiana, Laube. 

 Phyllocoenia decipiens, Laube. 



All these have been obtained by me from the bottom of the 

 Sutton Stone, and almost in actual contact with the floor of 

 Mountain-Limestone, but at one spot alone, and that only of very 

 limited extent. 



1 ' Fauna d. Schichten v. St. Cassian' pt. i (1865) pis. iii-vii. (Denkschr. d. 

 k. Akad. d. Wissensch. Wien, vol. xxiv.) 



2 'Monogr. Brit. Foss. Cor.' pt. iv, no. 1 (1867) p. 27. (Palseont. Soc. vol. xx.) 



3 Quart. Journ. Geol. Soc. vol. xl (1884) p. 372. 



4 Journ. Linn. Soc. (Zool.) vol. xviii (1885) p. 115. 



