STRXrCTTJRJB AJN'I) CLASSIFICATOKT POSITION OF MADEEPORARIA. 113 



9. On the Strtjctttre and Classipicatort Position of some Madre- 

 poRARiA from the Secondary Strata of England and South 

 Wales. By Prof. t. Martin Duncan, F.E.S., F.G.S., &c. 

 (Read November 4, 1885.) 



The Madreporaria of the Secondary strata of England were first 

 described in the volumes of the Palieontographical Society by MM. 

 Milne-Edwards and Jules Haime *, and some supplementary mono- 

 graphs were written by the author of this communication and 

 published by the same Society during 1866-1872. 



Ten years after the appearance of the last of the monographs a 

 series of papers was communicated to this Society by Mr. R. E. Tomes, 

 E.G.S., and these contained descriptions of new species and genera, 

 besides numerous criticisms of the work of the great French authors 

 and of my own labours. The criticisms occupy considerable space 

 in the ' Quarterly Journal of the Geological Society.' Many of 

 them have been answered in a " Revision of the Families and 

 Genera of the Sclerodermic Zoantharia " t ; but the time has now 

 come when a reply should be placed before this Society. 



As there was no particular order in Mr. Tomes's communications, 

 it is proposed to consider them in geological order, and the first to 

 be noticed is entitled " A Critical and Comparative Revision of the 

 Madreporaria of the White Lias of the Middle and Western CountiOvS 

 of England and of those of the Conglomerate at the Base of the 

 Welsh Lias" (Quart. Journ. Geol. Soc. vol. xl. 1884, p. 353). 



In this communication a number of genera and species were 

 passed in review, and amongst them the species of the genus Astro- 

 ccenia, which were described by me in the ' Monograph of the 

 British Fossil Corals,' 2nd series. Pal. Soc. Lend., part iv. no. 1, 

 1867. 



Some of the species described were very typical of the genus, and 

 most of them proved that, owing to a greater vigour of growth in 

 some places than in others, the united walls were thin and else- 

 where thick, and that the calicos were pentagonal and here and 

 there circular in outline. In no instance could a thin wall be found 

 around a calice separated from the walls of neighbouring calicos by 

 a cellular or coenenchymal tissue. All this can be readily seen in 

 the types, and the delineations by De Wilde are very fair. 



In an essay J on the Madreporaria of the Great Oolite, which pre- 

 ceded that now under consideration by a year, the following footnote 

 appeared. Mr. Tomes wrote : — " I take the present opportunity 



* Pal. Soc. Lond. 1850 and 1851. 



t Journ. Linn. Soc. Lend., Zoology, vol. xviii. (1884), "A Revision of the 

 Families and Genera of the Sclerodermic Zoantharia," &c. As this book will 

 be frequently referred to, it will be termed ** The Revision of the Genera." 



I Quart. Journ. Geol. Soc. vol. xxxix. 168, &c., p. 187. 



Q. J. G. S. No. 165. I 



