TILE CAEJ30NIEEE0ES FENESTELLID2B. 



181 



Phill., and Fenestella polyporata, Phill. There is also a peculiar 

 smoothness and regularity, in the growth alike of interstice and 

 dissepiment, which is attained by none of the other species and is 

 a distinguishing mark. The presence of three or four pore-cells in 

 a given space, the dissepiments, and the oblong fenestrates complete 

 the identity. Prof. M' Coy's fine drawing of this species is taken from 

 a partly worn-down specimen in which the sides of the interstice have 

 become sharp and angular, and the keel scarcely visible ; whereas the 

 interstice should have been full and rounded, and capped with a ridge 

 or keel, bearing the remains of spiny projections, while on either side 

 the cells stood out prominent and free. 



There is no doubt about the identity of this species with Gorgonia 

 antiqua, Goklf., although his figure is drawn from a much weathered 

 and mutilated fragment. It also agrees with Fenestella retiformis, 

 Schloth., the leading Permian species. I am aware that a contrary 

 opinion has been expressed. Virtually the species are the same. 

 Phillips was, in this country, the first to give a descriptive account 

 of it. His Fenestella irregularis, F. undulata, and F. jlustriformis 

 are all different portions of the polyzoary, under somewhat varying 

 conditions of growth and preservation. I cannot agree with Prof. 

 H'Coy in assigning Fenestella Jlustriformis to Ptylqpora* jlustri- 

 formis. As figured by Phillips, it is only the cast in limestone 

 of the reverse face ; and, as such, its relationship to Ptylopora 

 is purely conjectural. Prof. M'Coy was the first to recognize the 

 importance of this species, and to do justice to it in the way 

 of description ; and hence, although not its author, that it should 

 retain the name which he gave to it is generally conceded. In 

 this view I am borne out by Prof, de Koninck, who states ''• that 

 Lonsdale was the first to describe this species as Fenestella fossula, 

 but that his description was incomplete, and insufficient to recognize 

 it with certainty, whilst M'Coy's description was full and accurate"*. 

 Phillips's notice of it some years prior to that of Lonsdale was even 

 more incomplete. For the foreign synonyms of Fenestella pleheia 

 I am also indebted to Prof, de Koninck's work on the Carboniferous 

 Fossils of JSIew South Wales. 



Fexestelea meilbeaxacea, Phil. Geol. Yorks. pi. i. figs. 1-6. 



Fenestella flabellata, Phill. Geol. Yorks. pi. i. figs. 7-10. 



hemispherica, M'Coy, Syn. Carb. Foss. Irel. pi. xxix. fig. 4. 



IShumardii, Prout, Trans. Acad. St. Louis, p. 232. 



tenuifila, Phill. Geol. Yorks. pi. i. figs. 23, 24, 25. 



Sjp. char. — Base cylindrical, tapering to a fine point, with strong 

 non-poriferous rootlets attached. Tipper part widely expanded. 

 From nine to twelve inches in length, and five to eight inches in 

 width. Interstices rounded, straight, in parallel lines, keeled. Dis- 

 sepiments fine, slightly expanded at junction with interstice. Fenes- 

 trules oblong, slightly wider than insterstice, from two to three times 

 as long as wide. At one inch from base, five dissepiments in the 

 space of two lines measured vertically, and eight dissepiments in 

 * Foss. Pal. Nouv. Galles du Sud, 1877. 



Q. J. G. S. No. 146. o 



