ON THE OCCURRENCE OF THE GENTTS COLUMNARIA — ETHERIDGE. 33 



marginal ; in C. reticuluta, Salter,* 36, the primaries extending 

 half-way to the centre of the visceral chambers ; in G. franklini, 

 Salter,! although the number is not stated, they are very numerous 

 and evidently quite marginal, like those of C. calicina ; and in 

 C. gotlandica, Ed. & H.,J 36-44. The literature of those forms 

 described by Billings is not accessible to me, and I am thus unable 

 to enter into any comparison between his species and C. pauci- 

 septata. The great dissimilarity existing between the last-named 

 and those I have just quoted will at once be apparent, for in no 

 instance have I observed more than sixteen septa, a disparity 

 that can have no other than a specific significance. 



As compared with the tabular of other species, those of G. pauci- 

 septata may be said to be distant from one another. In G. alveolata 

 there are three in one line, horizontal or slightly flexuous according 

 to Nicholson, whilst Romenger says flat only; in G. calicina the 

 same; in G.? halli the tabulae appear to approach nearer to those 

 of our species in distance from one another, and are horizontal and 

 strong ; in G. reticidata the tabulje are " very close, four or five 

 in the space of a line " ; in G. franklini they are very closely 

 packed, about four in the space of a line," Both these Arctic 

 species, from the absence of mural pores, must be regarded as 

 Columnarice, although they have nmch the appearance of massive 

 Favosites of the F. gothlandica group, in which the walls have 

 undergone so much secondary alteration that the pores are not 

 visible, a fact well known to many microactinologists. Salter's 

 opinion, is borne out by the absence of any reference in Mr. 

 Etheridge's description § of mural pores in the same corals, collected 

 by the Nares Arctic Expedition. In C. gothlandica the tabulae 

 are said to be from one and a-half to two millimetres apart, even 

 more distant than in C. pauciseptata. 



The species of Columnaria are Silurian in their stratigraphical 

 distribution, both Lower and Upper, with the exception of a 

 doubtful Devonian form described by Schliiter.H 



The study of this coral leads me to support Prof. Alleyne 

 Nicholson's view that Columnaria cannot be placed near the 

 Favositidse, but as suggested by Prof. Verrill, and afterwards 

 adopted by the former, is much more nearly allied to the Astrseidse, 

 although I have not observed in C. pauciseptata any trace of 

 endothecal structures except tabulae. 



Type. In St. Stanislaus' College Museum, Bathurst. 



* Sutherland's Journ. Voy. Baffin's Bay, &c., 11., 1852, p. ccxxlx., t. 6, 

 f. 2, 2a. 



t Ihid., p. ccxxlx., t. 6, f. 3, 3a. 



X Archiv. Mus. Hist. Nat., v. 1851, p. 309. 



§ Quart. Journ. Geol. Soc, xxxlv., 1878, p. 586. 



II Abhandl. Geol. Speclalkarte Preuss.-Thiir. Staaten, viil., 1889, Heft 

 4, p. 14. 



