WHiTEAVEs] DEVONIAN FOSSILS OP MANITOBA, ETC. 269 



Group of Cyatho]))! yll Hin ( JSIothroplnjH iivi) (IrrorHraliuii, Billi 



lings. 



Cyathophyllum Athabascense. (Var.) 



Plate .S4, Hgs. S and !Sii. 



Oi/afhophi/lliiiii A/hahamni.se, Whiteaves. 1S91. This volume, p. 2()-2, pi. xxxii, 

 ligs. 1, la, b. 



Lake Winuipegosis, on the south western shore of Cameron Bay, J. B. 

 Tyrrell, 1889 ; a si<jgle and perfect specimen, which appears to be a mere 

 variety of this species. It differs from the types from the Devonian rocks 

 of the Athabasca River only in having its central area occupied Ijy flex- 

 uous, irregularly disposed but for the most part continuous tabuhe, rather 

 than h\ large interseptal di.ssepiments, and in its narrowei- vesiculose 

 peripheral zone, the inner margin of which is more clearly defined. 



(S.) COLUMNARIA (CyATIIOPHYLLOIDES) DIS.JUNCTA. (N. 8p.) 



Plate :U, fig.?. 3, 3a and 3b. 



Corallum composite, consisting apparently of a colony of cylindrical, 

 straight or Hexuous, ascending (ir erect corallites, which are .separate but 

 sometimes partially in contact, and more or less closely aggregated : diame- 

 ter of the corallites averaging about live millimetres, their mural invest- 

 ment single and external. iSurface markings of the corallites unknown, 

 though in transverse sections there are indications of longitudinal ribs cor- 

 responding to the septa within. Calyces deep, with erect sides : primary 

 septa thirteen, simple, neither crenulated nor denticulated, very thin, 

 laminar and extending to the centre at and below the Ijottom of the cup : 

 secondary septa similar in numbei' and structure to the primaries, but 

 reaching only half way to the centre. The only internal structures, 

 besides the septa, are rather distant, thin and laminar horizontal dia- 

 phragms, which partake partly of the nature of talauke and partly of dis- 

 sepiments. These diaphragms either form almost continuous ttooi's across 

 the corallites (at intervals of from one to twcj millimetres apart) and thus 

 resemble tabuhe, except that tlieir continuity appears to be interrupted 

 by the septa, or they are disconnected and not on the same plane and 

 thus partake more nf the nature of dissepiments, though they are nevei' 

 curved. 



Pentamerus Point, Lake Manitoba, J. B. Tyrrell and J. F. AVhiteaves, 

 l!S8S. South-west shore of Dawson Bay, Lake AVinnipegosis, at the 

 mouth of Steep Kock River, J. B. Tyrrell, 1S89. At each of these loca- 

 lities a few comparatively large portions i>f a single colony were collected. 



