390 Dr. H. A. Nicholson and Mr. A. H. Foorcl on a 



Genus Rhaphidopoea, Nich. & Foord. 



Corallum variously shaped, but mostly encrusting, or in 

 other cases massive. Corallites all of one kind, polygonal, 

 in close apposition, the walls of contiguous tubes being con- 

 fluent. Walls of the corallites imperforate. Calices poly- 

 gonal. Tabulae numerous, horizontal. Septal spines variably 

 developed, but always present, and consisting of conical 

 tooth-like projections, which extend only a short distance into 

 the visceral chambers of the corallites, and are not arranged 

 in regular vertical rows. Increase by gemmation. 



Type : RhaphidoiJora crinalis, Schliiter, sp. 



Rhaphidojwra crinalis^ Schliiter, sp. 

 (PI. XV. figs. 1-3.) 



Calamvpora cri/udis, Scliliiter, Sitzungsberichte der niederrheinischeu 



GesellscLait in Boun, 1881, p. 281. 

 Chcefetc's Lonsdalei, Eth., Jim., & Foord, Auu. & Mag. Nat. Hist. 1884, 



vol. xiii. p. 474, pi. xvii. figs. 2-2 c. 



Spec, cliar. Corallum sometimes encrusting, sometimes 

 laminar, sometimes massive, the latter being probably the 

 typical adult condition. Corallites polygonal, with completely 

 coalescent walls, averaging about ^ millim. in diameter, but 

 with dimensions in some specimens slightly larger or smaller 

 than this. Tabular are well developed, horizontal, and about 

 i to -g- millim. apart. The walls of the tubes are not specially 

 thickened, and often exhibit dark transverse lines, which seem 

 to connect adjoining visceral chambers, and which look like 

 mural pores filled up with some dark material. These cross 

 bars will be subsequently shown, however, to be due to mine- 

 ralization, and the walls are in reality imperforate. Septal 

 spines are variably developed, but are present in all well- 

 preserved examples, and have the form of strong tooth-like 

 projections, which extend a short distance into the visceral 

 chamber, and which, however numerous, are not arranged in 

 regular vertical rows. 



Ohs. This species is very variable in its mode of growth, 

 but its adult form seems to be usually that of a spheroidal or 

 pyriform mass. We have examined a large series of speci- 

 mens, most of which are from the Middle Devonian of Germany, 

 and which, like most of the more delicate coi-als from this 

 region, have undergone a good deal of change in the process 

 of mineralization. Hence there are various points in the 

 structure of the species which it is difficult to account for with 

 absolute certainty. In tangential sections of R. crinaUs 

 PI. XV. figs. 1, 2, and 3) the most striking feature is the 



