392 Dr. H. A. Nicliolson and Mr. A. H. Foord on a 



We shall further be able to show, iu dealing with R. stromato- 

 poroides, that these transverse markings in the walls of the 

 corallites are not of organic origin at all. Both transverse 

 and longitudinal sections of R. crinalis show that the walls 

 of the corallites are in no way specially thickened, and the 

 visceral chambers remain therefore distinct. Tabula (PL XV. 

 figs. 2 a, 3 a) are numerous, horizontal, and complete. 



The nearest ally of R. crinalis is R. stroniatopo7'oides, 

 Roem., sp. ; but the latter has on the average tubes of a deci- 

 dedly smaller size (averaging from i to j millim. in diam- 

 eter). At the same time it is to be noted that in neither of 

 these species are the corallites of an invariable size, since 

 examples of R. crincdis occur with tubes below the average 

 size, while specimens of R. stromatoporoides are found with 

 corallites of greater than the average dimensions. In such 

 cases it is difficult to decide positively to which of the two 

 species a given specimen belongs. As a rule, however, the 

 corallites in R. st7'oraatoporoides are not only decidedly 

 smaller than they are in R. crinalis^ but their walls are 

 mostly thicker and their visceral cavities are more rounded, 

 while peculiar rounded tubercular structures, the nature of 

 which is not quite clear, are often developed at the angles of 

 junction of contiguous corallites. 



Formation and Locality. Common in the Middle Devonian 

 of Sotenich and Gerolstein, in the Eifel. We have also 

 found it at Biichel (in the Middle Devonian of the Paffrath 

 district). Professor Schliiter's specimens were collected in 

 the Middle Devonian rocks of the Hillesheim basin, in the 

 Eifel. We have also examined specimens belonging to this 

 form from the Middle Devonian of Devonshire (Teignmouth; 

 Bishopsteignton, and Torquay). 



RliapMdojpora crinalis^ Schliit., var. aculeata, Nich. & Foord. 

 (PI. XV. figs. 4-4 &.) 



Corallum laminar and encrusting, the corallites of decidedly 

 larger size than is usual in R. crinalis, and being also of a 

 more compressed and elongated form. The tubes vary in 

 diameter from about f millim. to ^ millim. The walls of the 

 corallites are not thickened and are furnished with very 

 numerous tooth-like septal spines, which project a short dis- 

 tance into the visceral chambers. No signs of mural pores 

 can be detected unless the occasional occurrence of dark 

 transverse bars crossing the walls of the corallites in tan- 

 gential sections be taken as indications of the presence of such 

 openings ; but these, as in R. crinalis, must we think be 



