66 a. G. Carruthers — A Revision of some Carboniferous Corals. 



narrows rapidly from the outer to the inner end instead of expanding, 

 and ill the shortening of the cardinal septum very early in the growth 

 of the coral. Intermediate forms also exist, where the sides of the 

 fossula are parallel from end to end. These mutational forms will be 

 dealt with in a future paper on the evolution of the species. Meanwhile, 

 in my opinion, the name Z. delanoiiei should be restricted to those 

 corals where the fossula, in a section cut just below the calyx, is 

 clearly more expanded at its inner than its outer end, and where, 

 of course, the other characters of the species are present. Another 

 somewhat similar Visean Zaphrentid is Z. enniskilletii. This may be 

 distinguished from Z. delanouei by its larger size, a more irregular 

 outline of the fossula, and by an absence of the thickening and intimate 

 fusion of the inner ends of the major septa, so well seen in the latter 

 species, while the septa are more irregular in their disposition, and are 

 often discontinuous. 



It has, unfortunately, not been possible to obtain serial sections 

 of this beautiful species, suitable for reproduction, in an unbroken 

 condition, at any rate so far as fully grown forms are concerned ; the 

 large fossula and simple tabulae make the coral peculiarly liable to 

 fracture. The partially restored sections on PI. V, however, represent 

 the average of a considerable number of specimens, and it is hoped that 

 they will serve as accurate delineations of the mature coral. 



Distribution. 



Dr. Vaughan has kindly contributed some notes on the distribution 

 of Z. omaliusi and Z. delanouei in the South-Western Province. After 

 referring to the separation of Z. aff. phillipsi into these two species,^ 

 he says : — 



" Being convinced of the justification for this separation, I have 

 assiduously collected^ from the Zaphrentis-zonQ in the Bristol, 

 N. Mendip and Weston areas, with the view of determining the 

 distribution of these two species. The results of this revision are 

 highly satisfactory in their definiteness, viz. : — Z. delanoueiis practically 

 confined to Z^, being only doubtfully recorded from Zo of Portishead. 

 It is prolific at the base (Horizon /3), but rare in Upper Zg. 

 Z. omaliusi teems in Zg and at several levels in the lower part of 

 C. It is practically unknown from Z^ being very doubtf uUj^ recorded 

 from y3 of Burrington. In the Gower the resolution of Z. aff. phillipsi 

 into its component species has yet to be studied, but the results of 

 such revision will, however, in no way affect the zonal sub-divisions 

 established in the [Bristol] paper from the consideration of broad 

 faunal assemblages, in terms of which the distribution of the components 

 will have to be expressed. Since the distribution and structural 

 characters of the Zaphrentes and Campophylla in County Dublin have 

 an important bearing upon the correlation of the beds, and since the 

 Densiphyllid Zaphrentes are practically unknown except as rare 



1 As Dr. Vaughan informs me, the description of Z. aff. phillipsi in his original 

 paper ((J.J.G.S., vol. Ixi, p. 270) is only applicable in its entirety to Z. omaliusi. 



- " In this work I have received very valuable assistance from Mr. W. H. Wickes, 

 Professor S. H. Reynolds, and Mr. H. F. Barke ; Mr. Carruthers has uncom- 

 plainingly checked the identification of almost every specimen." 



