154 



(perhaps abnormally so) that the convexly arched region is obtusely 

 angulated in the centre, longitudinally ; in some young specimens this 

 region is distinctly flattened, but others are circular in outline in trans- 

 verse section, or as seen from above. Sgpta alternately long and short, 

 varying in number in large specimens from 160 to 170 in all, the longer 

 ones extending to the centre at the bottom of the calyx. Surface marked 

 with transverse wrinkles and numerous fine strise of growth in well- 

 preserved specimens, but often so much worn, apparently prior to fossili- 

 zation, as to be almost smooth. 



" Longitudinal sections through the centre of large specimens show that 

 the calyx is not very deep, and that its cavity occupies but a small 

 proportion of the entire length. Below the calyx the corallum is filled 

 with strongly developed and apparently thickened septa, with well- 

 marked dissepiments between them, and these septa, with their dissepi- 

 ments, unite in the centre in such a way as to form a large irregularly 

 reticulated pseudo-columella, which projects" slightly "above the centre 

 of the base of the calyx, as a boss of irregular shape, but with a narrowly 

 rounded summit. 



" This fine coral is especially abundant, and attains to a large size in 

 the Red River valley, at Lower Fort Garry and East Selkirk, Manitoba, 

 where it was collected by Dr. R. Bell in 1880, by T. C. Weston and A. 

 McCharles in 1884, by L. M. Lambe in 1890, and by D. B. Bowling in 

 1891." 



On the western side of Lake Winnipeg a few comparatively small and 

 very imperfect specimens, which may be referable to this species, were 

 collected at Deer Island by T. C. Weston in 1884, at Little Black Island 

 by J. B. Tyrrell in 1889, at Jack Head and Snake islands by D. B. 

 Dowling and L. M. Lambe in 1890, at Dog Head, Dancing Point, Little 

 Tamarack and Selkirk islands, and on the main shore opposite the north 

 end of Selkirk Island and north of the Saskatchewan by D. B. Dowling 

 in 1891. Most of the specimens from these localities appear to widen 

 out much more rapidly, at a short distance from the pointed base, than 

 any of the eastern examples of S. corniculum do, but a single specimen 

 from Little Black Island approaches very near to that species. 



A small specimen, which is probably also referable to S. robustum, was 

 collected at the junction of the Little and Great Churchill rivers by Dr. 

 R. Bell in 1889. 



When fully grown this species can be readily distinguished from S. 

 corniculu7n by its very much larger size and more robust habit of growth. 

 It seems to bear somewhat the same kind of relationship to /S. corniculum 

 that the Receptaculites Oweni of the Cambro-Silurian rocks of the west 

 does to the eastern fossil known by the rather inappropriate name of 



