CANADIAN FOSSILS. 33 



Caeabocrinus? tuberculatus, Billings. 

 Plate X. Figures 2a, 2b, 2c. 



Description. — Cup, sub-globular or broadly oval ; surface of plates 

 covered with small, rounded tubercles ; arms, large, long, several 

 times divided ; column, round, and in the upper part composed of 

 alternately thick and thin joints. 



Of this species we have only one specimen, and that is imperfect. 

 The distinctive characters are the tuberculated surface and large 

 arms. Although I have not seen the azygos inter-radials, yet the 

 general aspect of the specimen is so much like that of Carabocrinus, 

 that I have little doubt it belongs to that genus. 



Explanation of Figures. Platb X. 



Figure 2a. The only specimen collected. 

 " 26. Three joints of the column, enlarged. 

 " 2c. One of the joints of the arms, enlarged. 



Locality and formation. — Hudson River group, Charleton Point, 

 Anticosti. 



Genus PoROCRiNus, Billings. 



(PoROCBiNUS, Report Geological Survey of Canada, 1856, page 279.) 



FOEMULA : 

 Basal plates, 5. Regular inter-radials, 0. 



Sub-radials, 5. Azygos inter-radials, 2. 



Eadials, 1X5. 



rigure 13. 

 Figure 13. Diagram of the structure of the cup in the genus Porocrinus. 



Generic characters. — Cup, conical ; basal plates, five, pentagonal ; 

 sub-radials, five, three hexagonal and two heptagonal; primary 

 radials, five ; one large azygos inter-radial, supported on the trun- 

 cated summit of the anterior sub-radial, and one small one, situated 



c 



