﻿580 MR. A. WILMORE OK THE CARBONIFEROUS [NOV. I9IO, 



difficult it is to distinguish these species, unless we go hack to 

 Phillips's definition of Syringopora geniculata, and arbitrarily refuse 

 to recognize as that species any forms other than those that have 

 closely fasciculate coralla and the connecting tubuli very numerous 

 and coming off in subverticillate whorls. 



In 1883 Thomson l described some of the Syringopora found in 

 the Carboniferous rocks of Scotland. He recognized S. laxa, 

 Phillips, S. geniculata, Phillips, S. catenata (M'Coy), £. distant 

 (Fischer), and also mentioned S. ramulosa and $. reticulata. 



He also instituted a new species, S. gigantea, for specimens found 

 at Langside, Beith (Ayrshire). His description is as follows : — 



' Corallurn compound, and composed of long cylindrical and distant corallites, 

 and united by distant horizontal tubes, through which there is free communi- 

 cation throughout the colony. The epitheca is moderately stout, and there are 

 faint annulations of growth. There is a system of elongated convex cellular 

 tissue around the periphery, and there is a central tube extending throughout 

 each of the corallites. There are twenty minute septa, which are hardly 

 recognizable. Diameter of corallites, 2 lines.' 



I have already remarked that, in my opinion, S. laxa and 

 S. catenata may be included in other species, but I think that there 

 is a place for Thomson's new species, S. gigantea. I find in Craven 

 occasional specimens of a corallum which has wide and more distant 

 corallites than the usual coralla to which I should apjjly the names 

 JS. distans or S. ramidosa. To these rarer specimens I think that 

 the name S. gigantea may well be applied. 



We now come to the quite recent contribution of Dr. A. Vaughan. 

 In his Bristol paper, 2 he remarks, ' It is very doubtful whether the 

 so-termed "species" of this genus are anything more than circuli.' 



In the Rush paper 3 he writes : — 



' Stated broadly, dimensional variation is a function of environment, whereas 

 the degree of structural complexity is dependent on the earlier history of the 

 gens, and is, consequently, a function of the time.' 



Dr. Vaughan recognizes forms which are similar to S. distans, 

 S. geniculata, S. ramidosa, and S. reticulata. He also describes a 

 ' species ' under the name Syringopora 6, Vaughan, which is some- 

 what like S. laxa, Phillips. It will be noticed from his description 

 that this species is closely allied to S. gigantea, Thomson ; but the 

 corallites are not so widely apart as in Thomson's diagrams, nor 

 so widely apart as in the coral which I class as S. gigantea from 

 Craven. 



As I have already pointed out, Syringopora is exceedingly 

 plentiful in some parts of Craven, and I think that there is sufficient 

 material to justify some conclusions bearing on the various questions 

 which have been raised by the writers whose work I have briefly 

 summarized. 



1 Proc. Phil. Soc. Glasgow, vol. xiv (1882-83) pp. 328-32. 



2 Quart. Journ. Geol. Soc. vol. lxi (1905) p. 268. 



3 Ibid. vol. lxii (1906) p. 313. 



