CANADIAN FOSSILS. 61 



Glyptoceinus LACUNOSUS. 

 Plate VIII. Figures 3a-3e. 



(G. LACUNOSUS, Report Geological Survey of Canada, 1856, page 261.) 



Description. — This species is characterized by its very large basal 

 plates, one of which, that beneath the azygos inter-radial space, is 

 hexagonal, and supports upon its upper truncated edge the first 

 azygos inter-radial. The surface of the body is completely covered 

 with small rugose pits and wrinkles ; the rays become free at the 

 second or third secondary radial plate ; they divide immediately after 

 becoming free, at least once, perhaps again above, but the specimens 

 do not shew them perfectly above the first sub-division.. The body 

 is sub-globular, about three-quarters of an inch in length, and the 

 same in breadth. 



The column is round, and when once carefully examined is easily 

 distinguished from that of any other species occurring in the Trenton 

 limestones. The large joints are proportionally very broad and 

 projecting, while the constrictions between them are wide and deep. 

 At the distance of from six to ten inches from the base of the cup 

 the large joints disappear altogether, and the column becomes 

 smooth, like that of the genus Rhodocrinus. In one specimen, at 

 the distance of three inches from the base of the cup, the large 

 joints are nearly one line in thickness at their edges, and are two 

 lines distant from each other ; they are also two and a half lines in 

 diameter ; the constricted portion of the column between them is 

 scarcely one line. 



Explanation of Figures. Plate VIII. 

 Figure 3a, A specimen with part of the column attached. 

 " 36. Fragment of a different specimen. 

 " 3c, 3d, 3e. Columns of this species. 



Locality a?id formation. — Upper half of the Trenton limestone, 

 City of Ottawa. 



Rhodocrinus pteifoemis, Billings. 



Plate VI. Figures la-Id. 



(THT3AN0CEINUS [Rhodocrinus] pteipormis. Report Geol. Survey of Canada, 1856, p. 263.) 



Description. — Cup, conical or pyriform, the adult specimens about 

 two inches in length and one inch and a half iti their greatest 



