﻿114 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



[Jan. 22, 



the diaphragms being on different levels (fig. 6 -f near the bottom and 

 left side), the continuous line representing the boundaries of two con- 

 centric layers*. It is further stated more than once f, that transverse 

 laminae are wanting in tubular Bryozoa or Ascidian polypes ; but are 

 characteristic of Anthozoa (Zoantharia) ; yet their existence in the 

 lower greensand fossil is not denied by M. M. -Edwards and M. 

 Haime. In the specimens examined, the structure was frequently 

 absent, being one of the most perishable portions of stony corals ; but 

 it occurred sufficiently often to prove, that it was an essential com- 

 ponent of Choristopetalwnimpar\ ; it is moreover, even when present, 

 not always easily to be detected in tubes of very small calibre. In 

 Chcetetes, the want of cross laminae was one of the characters on which 

 the genus was founded, but that diaphragms exist in the typical spe- 

 cies cannot be doubted. If it should be urged that cross laminae are 

 not a constant structure among Corallaria, being totally wanting in 

 true Alcyonice, it must be stated, that either diaphragms or an equi- 

 valent component prevail throughout the class generally ; while it 

 remains to be shown that they occur in any genus of Bryozoa. The 

 suborder Zoantharia tabulata of M. M. -Edwards and M. Haime is 

 based on their existence §. One of the peculiarities of the lower 

 greensand coral is the facility with which it separates into layers on 

 mechanical force being rightly applied ; and examples of the severed 

 surfaces are represented by figs. 7 and 8 1|, the characters thus dis- 

 played agreeing also with those of tolerably preserved exteriors^. 

 The larger openings, in both cases, led directly into the visceral tubes ; 

 but they might be mistaken for the apertures of cells, or of tubes 

 limited in extent to the thickness of a layer. It is however stated 

 in the description**, that the under surface of the detached portion 

 presented a counterpart to the surface from which it had been 

 severed, or apertures of similar dimensions ; and that the former had 

 manifestly been moulded on the latter. The larger openings consti- 

 tuted, therefore, a direct communication from layer to layer, and 

 were not the apertures of cells or short tubes, but had been, for a 

 time, the upper extremities of continuous tubes or visceral cavities 

 periodically elongated and crossed at irregular intervals by dia- 

 phragms. It is therefore believed that the fossil was rightly assigned 

 to the class Anthozoa {Zoantharia), and the author must maintain 

 that opinion till the data are shown to be erroneous. 



II. With respect to Cyathophora? elegans, M. M. -Edwards and 

 M. Haime state, that they do not quite understand the reasons by 

 which the describer was guided in referring with " a sign of doubt" 

 the lower greensand fossil to the Cyathophora of M. Michelin, a genus, 

 which, in their opinion, does not differ from true Stylinaff. It is 



* P. 72, last 1. and p. 73. 



f P. 68, 1. 6 from bottom, p. 70, 1. 12-21 and 1. 7 from bottom. 

 t P. 71, 1. 32-35. 



§ Comptes Rendus, 1849, p. 260. Palseontographical Society, vol. for 1850, 

 Mem. Brit. Foss. Corals, Introduction, p. lvii. 



|| Quart. Journ. Geol. Soc. vol. v. pi. 4 ; consult also p. 72, last line, and p. 73. 

 H Fig. 11, and p. 71, 1. 21. ** P. 73, 1. 17 from bottom et seq. 



f t Pal. Soc. vol. for 1850, p. 71. 



