522 On anew Genus of Devonian Corals. 



RhapUdopora ? sp. (PL XVII. figs. 7-10.) 



We have seen that both R. crmalis^ Schliit., and R. stro- 

 matoporoidesj Roem., occur in the Devonian rocks of Devon- 

 shire. We have here figured slides of two other examples of 

 Rhaphidopora which we have from the same formation and 

 which we are unable to identify with certainty. One of these 

 (PI. XVII. figs. 7 and 8) exhibits rounded thick-walled tubes, 

 intersected by complete horizontal tabulfe, but apparently 

 without septal spines. The diameter of the tubes is on an 

 average about a third of a millimetre. The specimen from 

 which these slides were taken was collected by Mr. Champer- 

 nowne in the Middle Devonian Limestone of Dartington, and 

 forms a mass of considerable size. The specimen is highly 

 mineralized, and the absence of the septal spines may be due 

 to this. It is not improbable, therefore, that this is only an 

 altered example of R. crinalis^ Schliit. 



The other specimen to which we refer (PL XVII. figs. 9 and 

 10) is from Teignmouth, and agrees with the preceding in the 

 general dimensions of its tubes and the apparent absence of 

 septal spines. Its distinguishing feature is the angularity of 

 the corallites and their comparatively irregular shape. This 

 specimen also is much mineralized and does not admit of 

 positive specific characterization ; it cannot even be stated 

 with certainty to belong to the genus Rhaphidopora at all. 



EXPLANATION OF PLATE XVII. 



Fig. 1. Part of the vertical section of a double colony of R. crinalis, 

 Schliit. (?), enlarged twelve times, in which one colony is 

 normal and the other is in the " stellimicans " state. This may 

 be only an example of R. stromafoporoides, Roem., with unusually 

 large tubes. Middle Devonian, Gerolsteiu. 



Fiff. 2. Part of a tangential section of R. stromatoporoides, Roem., in the 

 " stellimicans " state, enlarged twenty times. The tubes are 

 below the average size. Middle Devonian, Gerolstein. 



Fig. 3. Part of a tangential section of R. stroinafoporoides, Roem., en- 

 larged twenty- four times. The walls of the corallites are highly 

 crystallized, and are completely fused with their crystalline 

 lining, no longer appearing as distinct structures in the portion 

 of the section figured. The centres of the visceral cavities are 

 still unoblite rated, and they are joined by regular radiating lines, 

 the result of stellate crystallization. Middle Devonian, Gerol- 

 stein. 



Fig. 4. Vertical section of a specimen of R. stromatoporoides, Roem., 

 which is wholly in the ^'stellimicans" state. It consists of 

 several superposed colonies, of which the lowest has tubes of 

 much larger size than the others, and mag belong to R. crinalis, 

 Schliit. Enlarged twelve times. Middle Devonian, Gerol- 

 stein, 



