ne\o Genus of Devonian Coras. 893 



interpreted to be the result of mineralization. The tabulae 

 are numerous, complete, and about ^ millim. apart. 



This hardly seems to be more than a well-marked variety 

 of R. crinalis, Schllit. It is distinguished by the larger 

 average size of its corallites and their more compressed form, 

 and, above all, by the extraordinary development of the septal 

 spines. These structures are not only exceedingly numerous 

 (PI. XV. fig. 4 a) , but they can be readily recognized in 

 longitudinal sections of the corallites as well as in tangential 

 ones. In sections of the former kind (PI. XV. fig. 4 b) they 

 are shown as strong, upwardly-directed, tooth-like spines 

 developed from the walls of the corallites, and their cut ends 

 are also seen as dark circular spots (which must not be mis- 

 taken for mural pores) in the cavities of the tubes themselves. 



Formation and Locality. Middle Devonian, Gees, near 

 Gerolstein, in the Eifel. 



Rhaphidopora stromatoporoides^ Roemer, sp. 

 (PI. XV. figs. 5-7 a and PI. XVI. figs. 1-7.) 



Chcetetes stromatojmroides, Ferd. Koemer, Letliaea Palseozoica, p. 459, 



fig. Ill (1883). 

 Pachytheca stellimicans, Schliiter, Sitziingsberichte der niederrheinischen 



Gesellschaft in Bonn, 1885, p. 144. 

 Calamopora pilifcrrmis, Schliiter, ibid. p. 144 (footnote). 



Spec. char. Corallum laminar, most commonly composed 

 of successive colonies of varying thickness, and very often 

 attached by the whole of the inferior surface to some foreign 

 body. Corallites polygonal, in close contact, with coalescent * 

 walls, averaging from :^ to ^ millim. in diameter, but some- 

 times falling below or exceeding these dimensions either 

 wholly or in part. Walls of the corallites moderately thick- 

 ened, the primordial wall being occasionally visible as a thin 

 dark line in the centre of the apparently single wall separating 

 the visceral chambers of adjoining corallites (PI. XVI. fig. 1 16, 

 upper part). The visceral chambers of the corallites may be 

 filled with clear crystalline calcite (as usual), with the tabular 

 intact ; but in many cases they are more or less extensively 

 encroached upon by a darker matrix, and the walls and the 

 tabula obliterated by the development of a peculiar structure, 

 which we shall subsequently show to be of a purely inorganic 

 nature. At the angles of adjacent corallites are often deve- 

 loped peculiar tubercular thickenings, the nature of which is 

 not apparent. Tabulse are numerous and horizontal, mostly 

 from §■ to ^ millim. apart. Septal spines are variably deve- 

 loped, but usually less numerous than in R. criaalis. Walls 

 imperforate. 



