tiew Genus of Devoman Corals. 391 



presence in the corallites of a variable number of strong tooth- 

 like projections, which extend a short distance inwards into 

 the visceral chamber. Sometimes there may be onlj one of 

 such projections visible in a given corallite, or there may be 

 several. When only a few of these structures are present 

 they have a close general resemblance to the curious inward 

 projections of the walls which characterize the genus Chcetetes, 

 Fischer. In the latter, however, these projections are un- 

 doubtedly the result of the fission of the tubes. On the other 

 hand, in R. crinalis they are of a different nature, being in- 

 contestably of the character of septal spines. That this is 

 their true nature is conclusively shown by the fact that they 

 are not only, on the whole, far more numerous than are the 

 apparently similar projections in Chcetetes, but a single coral- 

 lite may have four or five or more of such teeth exhibited in 

 transverse section, a condition which would be impossible if 

 they were due to fission of the tubes. These tooth-liiie pro- 

 jections, in fact, bear a marked resemblance to the peculiar 

 septal spines of the so-called Alveolites Batter shyi, E. & H. 



A more difficult point to be assured of is, as to whether or 

 not mural pores are present in U. crinalis. This problem was 

 decided in t)ie affirmative by Prof. Schliiter, upon the ground 

 that the walls of the corallites commonly exhibit dark trans- 

 verse bars, as seen in tangential sections, and that such bars 

 must be mural pores filled up with matrix. Similar trans- 

 verse bars intersecting the walls of the corallites in tangential 

 sections are seen in all the species of Rhaphidopora which 

 have come under our notice, and they are sometimes very 

 numerous and very regular in their distribution and arrange- 

 ment. At first sight, they certainly present a resemblance to 

 mural pores filled up by some dark material ; but there are 

 several reasons of a general nature from which it must be 

 concluded that this cannot be their true constitution. Thus, 

 it is incredible that these transverse markings should be so 

 numerous as they often are in the species of Rhaphidopora if 

 they are really due to mural pores ; since in tangential sec- 

 tions of species of Favosites, Alveolites, and Michelinia, in 

 which mural pores are well known to exist, it is a compara- 

 tively unusual thing to find them in transverse sections of the 

 tubes. Again, it is in the highest degree improbable that 

 these markings should be due to mural pores, and that no 

 traces of the existence of such apertures should be capable of 

 detection in longitudinal sections of the corallites of Rhaphido- 

 pora crinalis. We have, however, never succeeded in demon- 

 strating their presence in vertical sections of this or of any other 

 species oi Rhaphidopora, and are satisfied that they do not exist. 



27* 



