70 CONTEIBUTIONS TO CANADIAN PALAEONTOLOGY. 



by Hall (op. cit.) was obtained are seen further to the east in the Mani- 

 toulin Islands. The original description is as follows — " Coral massive, 

 or hemispheric ; cells quadrangular or sub-oval ; walls thin; interspaces 

 rarely thicker than the walls ; arranged in a single series, in wide irregular 

 reticulations. This species differs from the C escharoides in the almost 

 quadrangular form of the cells and the extremely thin walls, the reticula- 

 tions are wider and the whole aspect less solid than in that species. 

 From C. aggloinerata, it differs essentially in the form and arrangement 



of the cells." " Eastern shore of Green Bay, Wisconsin." What 



is particularly noticeable in this variety is the marked angularity of the 

 corallites, their sides being flattened, and the apparent absence of tubules 

 between them. The longitudinal rows of septal spines are beautifully 

 preserved in some specimens, especially in a few from East Selkirk, Mani- 

 toba. The variability of the size of the meshes is again seen in this 

 variety, showing that something apart from the mere shape of the coral- 

 lum is necessary for differential use. 



Halysites catenulaeia, var. micropoea, Whitfield. 

 Plate III., fig. 4. 



Halysites catenulatus, var. microporus, Whitfield. 1882. Geol. of Wisconsin, vol. IV., p. 



272, pi. XIII., fig. 6. 



In the Niagara formation of Ontario specimens are met with that 

 have very small corallites. These are similar to the specimen, already 

 mentioned, from near Donald, B.C. ( Silurian ) and one from the 

 Jumpers, Anticosti ( Silurian ). In most of the specimens seen the 

 meshes are rather small, but in some they are comparatively large and 

 irregular. In none, however, was the inside structure seen by means of 

 sections, so that the writer is unable to state whether tubules are present 

 or not, nor could this be decided from the fossils when examined at the 

 sijrface. 



This form appears to be similar to ZT. catenularia, var. micropora, 

 Whitfield, from the Niagara group of Wisconsin ; its corallites are of about 

 the same size, nearly twenty occurring in the space of 1 inch. 



Pending further knowledge of the details of its structure, this small 

 form is, for the present, referred to the Wisconsin variety. 



Halysites catenulaeia, var. simplex. (Var. nov.) 



Plate IV., figs. 3, 3a. 



The principal characteristics of this variety are, the large size of its 

 corallites, its long narrow meshes and the absence of tubules. A single 



