lambe. ] CANADIAN PALAEOZOIC CORALS. 131 



Locality and formation — Near Woodstock, Ont., collected by A. Mur- 

 ray in 1857 ; Corniferous limestone. 



In the original description of A, Yandelli, from the Falls of the Ohio, 

 no mention is made of a particularly slight development of the secondary 

 septa such as is seen in the Woodstock specimens, in fact in the figures 

 these septa are shown as being comparatively long ; also in the references 

 made to the species by Billings, Nicholson and Rorainger very little is 

 said about the septa and nothing from which it might be inferred that 

 the secondaries consisted of tubercles only. 



Amplexus exilts, Billings. 



Plate IX., figs. 5, 5a, 5b. 



Amplexus exilis, Billings. 1874. Canadian Naturalist, new series, vol. VII., p. 232. 



Original description. — " Corallum more or less curved, expanding to a 

 diameter of 14 lines at 3 \ inches from the base. Surface with very dis- 

 tinctly defined costal striae, of which there are 5 in the width of 3 

 lines, where the diameter is about one inch, and 6 or 7 in the same space 

 at the base. There are about 64 septa where the diameter is 14 lines. 

 The larger of these are scarcely a line in depth ; the smaller about half 

 that size. The tabula? are very thin, flat or slightly undulating, distant 

 from each other from 1 to 6 lines. 



" Owing to the fragile character of the shell, good specimens of this 

 species are rare. The best in our collection consists of the lower 6 inches 

 partly imbedded in the rock. By the application of acid, the whole of 

 the interior has been completely freed from the limestone which filled it, 

 so that it shows the tabuhe and septa perfectly. It is curved somewhat 

 irregularly to a radius of between 4 and 5 inches. There are numerous 

 small rings of growth, in general not very prominent, but with some that 

 are angular and strongly elevated. These are, sometimes, so deep that 

 they give to the costal striae, a nodose appearance. 



"The extremely rudimentary state of the septa, distinguishes this 

 species from all the described American forms known to me." (Billings.) 



Locality and formation. — Corniferous limestone cf Ontario. 



Genus Pycnostylus, Whiteaves. 



Pycnostylus, Whiteaves. 1884. Palteoz. Foss., vol. III., pt. I., p. 2. 



Generic characters. — " Internal structure very similar to that of Am- 

 plexus , the radiating septa being rudimentary and extending but a short 



