54 CANADIAN FOSSILS. 



also variously notched. In the species G. Logani, G. Forbesi, and 

 G. gracilis, many of the plates have re-entering angles, but in their 

 arrangement in the walls of the cup they form regular series. 



The pectinated rhombs also exhibit some peculiar new features. 

 In no other genus have more than three been observed, and these, 

 in all the genera except EcJwio-encrinites, are placed one at the base 

 of the dorsal side and two in the upper half of the body, as in the 

 genus Pleurocystites. The surface of Ghjptocystites shews that three 

 is not the constant number. It was also supposed to be essential to 

 these organs that each should occupy two contiguous plates, about 

 half of the rhomb being upon one and the other half upon the other. 

 In Glyptocystites we have the new character of-half rhombs in all the 

 four species. Generic name from glyptos, sculptured. 



Glyptocystites at one time appeared to me to be so closely related 

 to Echino-encri7iites, that I had much doubt as to the propriety of 

 retaining the name. After having examined a number of good 

 specimens of the Russian genus, in the Museum of Practical Geology, 

 London, I am satisfied that there is no generic affinity between them, 

 except in the presence of the two rhombs in the dorsal side of the 

 base. In no other respect is there any near relationship. That the 

 number and arrangement of the plates are the same in both genera, 

 is not a character sufficient to unite them ; otherwise we should be 

 obliged to make but one genus of Pseudocrinitcs (Pearce), Apiocystites 

 (Forbes), Prunocystites (Forbes), Eclmio-encrinites (Volborth), Lepado- 

 cfmites (Conrad), and Glyptocystites. In all of these there are four 

 series of plates, as follows : Four basal plates, and five in each of 

 the second, third and fourth series. If we seek for other characters, 

 we find that the Russian genus consists of several species, which, 

 taken together, constitute a group having in its general aspect no 

 resemblance whatever to that group formed by the four species of 

 the American genus. The European species have short angular 

 bodies covered with thick plates, the ventral side sometimes greatly 

 projecting, and only three pectinated rhombs obscurely developed ; 

 while all the species of our genus have elongated sub-cylindrical 

 bodies, nearly covered with rhombs, some of them of a large size. 



VII. Glyptocystites multiporus, Billings. 

 Plate III. 



{Canadian Journal, vol. ii. p. 215, 1854; Geol. Survey of Canada, Report, 1856, p. 281.) 



Description. — One inch in length, five lines in diameter, cylindrical, 



