22 M. G. Carruthers — A Heviswn of some Carboni/erous Corals. 



The corals in the Piret Collection were first of all compared with 

 those in the Musee Royale d'Histoire Naturelle at Brussels, to ensure 

 their identity with de Koninck's figured specimens. A certain number 

 were then cut, the transverse sections serially and at right angles 

 to the axis of the coral, the vertical sections mostly down the centre 

 of the cardinal fossula, a few also being cut in a vertical plane, 

 between the fossular depressions. 



Both internal and external characters of the various species being 

 then known, it was possible to recognise and examine further 

 examples in other collections, and make some notes on variation and 

 distribution. These latter observations, however, cannot pretend to 

 have any great value or completeness. Very much more work 

 requires to be done before the zonal value of these small corals can be 

 ascertained. The evidence at present available is so scanty, and the 

 districts that have been thoroughly searched are so few, that it must 

 be some time before de6nite conclusions on this point can be stated. 

 Some general observation on the results so far attained will be found 

 at the conclusion of the paper. 



My indebtedness to many sources of information and assistance is 

 great. I'irst of all, my sincere thanks aie due to the authoiities at 

 the British Museum (Natural History) for permission to examine and 

 cut the very beautiful corals in the Piret Collection, and to the 

 Geological Survey for facilities in the investigation ; without such aid 

 this work could not have been undertaken. I also wish to thank 

 MM. Duj)ont and E.utot, of the Musee Koyale d'Histoire Naturelle, 

 Brussels, for their courtesy in allowing me to examine the collections 

 there preserved. 



It is hardly possible to adequately acknowledge the kindness of 

 Dr. A. Vaughan in allowing me to make the freest use of his extensive 

 collections from the Bristol district, for a constant supply of fresh 

 material, and for the most generous and ungrudging assistance 

 throughout. I am also indebted to Dr. Matley and Dr. Vaughan for 

 material from the Hush area (co. Dublin), and similarly to Professor 

 E. J. Garwood, and to the members of the Yorkshire Geological 

 Society, for material collected in the Arnside and Colne-Clitheroe 

 districts respectively. Finally, I wish to sincerely thank the Trustees 

 of the Sladen Fund for a grant in furtherance of this work, without 

 which the accompanying illustrations could not have been so numerous 

 or complete. 



Septal Fokmaxion and Terminology. 



Before proceeding to the description of the species, it may be of 

 assistance to the general reader that attention should here be drawn 

 to the peculiar mode of septal formation, so characteristic of Rugose 

 corals, since an acquaintance with the facts concerned explains many 

 difficulties and apparent anomalies met with during an examination of 

 these corals, especially with regard to the fossulae. 



As- it was not till 1870 that Kunth ' first established his law of 

 growth, many years after the appearance of MM. Milne-Edwards and 



» Zeit. Deut. Geol. Ges., vol. xxi (1869). 



