502 Dr. H. A. Nicholson and Mr. A. H. Foord on 



minor, M'Coy, the originals of which were also obtained from 

 the Carboniferous Limestone. Phillips's specimen of F. in- . 

 crustans is not well preserved, especially as regards its external 

 surface ; but we are not able to see in thin sections of it any 

 characters which would in any way separate it from F. minor, 

 M 'Coy. Under these circumstances the species must stand as 

 Fistulipora incrustans, Phill., sp., and M'Coy's name must 

 hence be regarded as a synonym. 



As to the propriety of ranking the fossil which M'Coy 

 described {loc. cit.) under the name of Berenicea megastoma, 

 as also a synonym of Fistulipora incrustans^ we cannot speak 

 with the same certainty, since we have had no opportunity of 

 examining McCoy's original specimen. There can, however, 

 be no doubt that the fossil which has usually been identified 

 (notably by Mr. Vine and Mr. John Young) with Berenicea 

 megastoma, M'Coy, is truly the young stage of Fistulipora 

 incrustans. Mr. John Young [loc. cit.) has fully demonstrated 

 this point. Whether, however, the fossil usually identified 

 with Berenicea megastoma, M'Coy, is really the fossil so 

 named by M'Coy is a point which could only be positively 

 decided by an examination of M'Coy's original example. 

 We are, however, disposed to believe that the identification is 

 correct, and we therefore place Berenicea megastoma, M'Coy, 

 as a synonym of F. incrustaiis, Phill. 



On the other hand, the Carboniferous coral described by 

 one of us (Nicholson, Pal. Tab. Corals) under the name of 

 Fistulipora minor, M'Coy, appears to be a distinct but closely- 

 related species, to which we shall here give the name of 

 F. muscosa. It does not differ essentially, however, from 

 typical examples of F. incrustans, Phill. { = F. minor, M'Coy), 

 in anything except the rather smaller dimensions of the auto- 

 pores and the proportion which these bear to the mesopores. 



The most distinctive characters of the minute structure of 

 F. incrustans are the comparatively large size of the auto- 

 pores and their being usually separated by no more than one 

 or two rows of luesopores. The general shape of the auto- 

 pores is oval or circular, and the trifoliate form of the tubes in 

 cross section is not nearly so marked as it is in many species 

 of Fistulipo7'a, though it is quite commonly recognizable. 

 That the autopores really have the form characteristic of the 

 genus is shown not only by tangential sections, but also by an 

 examination of the actual surface, many examples showing the 

 peculiar arching of one side of the aperture of the autopores 

 which is associated with this peculiar type of corallites. 



F. incrustans shows clearly, as does its near ally F. muscosa^ 

 the interesting phenomenon of the increase of the mesopore^ 



