50 



BRITISH STROMATOPOROIDS. 



simply enclosed by the vermiculate fibres of the ccenosteum, precisely as are the 

 zooidal tubes in Mlllepora. There is, it need hardly be pointed out, no relationship 

 between the tubes here in question and the occasionally present axial tubes of the 

 radial pillars ; nor have these tubes anything in common with the comparatively 

 large walled tubes of the so-called " Caunoporce," whatever view we may take as 

 to the nature of these latter structures. There can not, in fact, be the smallest 

 question but that the minute vertical tubes of Stromatopora belong to the 

 ccenosteum proper ; nor does there appear to be any reasonable ground for doubting 

 that they served for the lodgment of the zooids of the colony. This conclusion is, 

 in my opinion, rendered absolutely certain by the fact that in all the typical species 



Fig. 6. 





I 

 - 



C D 



Fig. 6.— A. Tangential section of Stromatopora Bilpschii, Barg., sp., enlarged twelve times, showing 

 the reticulate skeleton and the porous structure of the skeleton-fibre. B. Vertical section of the 

 same, similarly enlarged, showing the tabulate zooidal tubes. C. Tangential section of Stromatopora 

 bucheliensis, Barg., sp., enlarged twelve times. D. Vertical section of the same, similarly enlarged. 

 From the Devonian Limestone of Biichel (Paffrath district). Both these forms commonly occur in 

 the " Caunopora " state, and were referred by Bargatzky to Caunopora, Phill. 



of the genus Stromatopora (such as 8. concentrica, Goldf., 8. Hilpschii, Barg., S. 

 biicheliensis, Barg., 8. antiqua, Nich. and Mur., 8. discoidea, Lonsd., S. typica, Rosen, 

 8. Beuthii, Barg., 8. Carteri, Nich., &c), these vertical tubes are crossed by more or 

 less numerous, complete, transverse, calcareous plates, which in all respects agree 

 precisely with the "tabula?" of the Hydrocoralline genus Millepora and of the 

 so-called " tabulate " Corals. I give here sketches of two characteristic species of 



