WHiTEAVEs] DEVONIAN FOSSILS OF MANITOBA, ETC. 271 



millimetre to two millimetres. Most of the tabulae are complete and 

 stretch completely across from one side of the inner wall to the other, but 

 they sometimes inosculate and occasionally one or two incomplete ones, 

 are intercalated between two of the others. 



Dr. Freeh, who has examined the specimens collected by Mr. Dowling, 

 is of the opinion that they belong to the genus Amplexus and that they 

 are nearly related to the A. Hereynicu.-< of A. Romer, from the Stringo- 

 cephalus limestone of Germany. Dr. Freeh thinks that the supposed 

 inner wall of the tubes, represented on Plate 3.5, fig. 2a, is caused by the 

 cutting of the curved tabulw. On the other hand, there are clearly disse- 

 piments between the specimens from Dawson Bay, which are stated to be 

 wanting in Amplexus, and there is a, remarkably close resemblance, in 

 size, shape and internal structure, between these specimens and the Di- 

 phi/phyllum stramineum of Billings, which Dr. Rominger says is both con- 

 generic and conspecific with the Eridophyllum Simcoease of the same 

 author, and which therefore should be called D. Simcoense. In the actual 

 types of D. stramineum, however, the central area of the corallites is not 

 separated from the peripheral cycle by an internal \i all (as pointed out by 

 Dr. Rominger), the septa are unequal in length and extend much farther 

 inward than do those of the Dawson Bay specimens, and the tabulae are 

 straighter and more regular in their disposition. 



(S.) ACTINOCYSTIS VARIABILIS. (N. Sp.) 



Plate 35, figs. 3 and 3a. 



Corallum simple, slightly curved, varying in shape from broadly turbi- 

 nate and widely expanding, with the breadth at the summit exceeding 

 the height, to cylindro-conical and somewhat contracted at the summit ; 

 outer surface apparently almost smooth and marked onlj' with a few trans- 

 verse wrinkles ; calyx rather deep, conical, narrow at the base ; septa 

 about eighty five in number, extending from the exterior to within a, short 

 distance from the centre, but feebly developed, thin, and rarely, if ever, 

 quite straight, their regularity being frequently disturbed by anchylosis 

 with the walls of the interseptal vesicles. Internal structure, apart from 

 the septa, essentially the same as that of Cystipliylhun, and consisting 

 exclusively of coarse vesicular tissue. The vesicles are very large in the 

 central area and diminish gradually in size towards the periphery. As 

 viewed in longitudinal sections, they appear as lenticular cells which radi- 

 ate obliquely upward and outward from the centre of the coral. 



" Western shore of Dawson Bay," Lake Winnipegosis, " from slabs ap- 

 parently derived from the neighbouring cliffs," J. W. Spencer, 1874 : one 

 small specimen, which was referred to by E. Billings as a '^ Heliopliyllum 

 September, 1892. 2 



