174 



THE CRINOIDEA CAMERATA OF NORTH AMERICA. 



^^u^Ci? 



introduced in the growing Crinoid in great numbers among the primary 

 interradials and interdistichals, and between these and the basals, radials, 

 and brachials. The interradial and interdistichal spaces throughout this 

 group are greatly depressed, and the plates succeeding the radials folded 

 into conspicuous ridges. This structure, combined with the more or less 

 rudimentary character of the interposed plates, is so unique and remarkable, 



that all other characters, some of 

 which in other groups are charac- 

 teristic of very distinct families, 

 appear to be subordinated to it, 

 and we are compelled to unite 

 under this family both monocy- 

 clic and dicyclic forms ; those in 

 which the radials are all sepa- 

 rated, and those in which they 

 are in lateral contact at four sides. 

 We think that few, after seeino^ 

 a large number of specimens, will 

 doubt the propriety of this course ; 

 for the structure in question pro- 

 duces a habitus so distinct and 

 predominant, that it is only by 

 means of these characters that the 

 three genera of this family can be separated. 



In our classification of 1885,"^ we proposed the genus Canistrocrinus upon 

 two species, which according to the descriptions differed from all genera 

 previously known. In defining the genus we relied upon the correctness of 

 the figures; but these have proved to be misleading in some very important 

 points, and we are compelled to withdraw it. As to "Canistrocrinus'' Richard- 

 soni {Glf/ptocrinus Richardsoni Wetherby), we are now convinced that it is 

 a Glf/ptocriniis, and identical with Glijptocriniis siihglohostis Meek. It has well 

 defined interradials, and the anal plate rests vpon the radials, and not hehueen 

 them. The other species, ^'Canistrocrinus''' Pattersoni {Gli/ptocrinns Ratter soni 

 S. A. Miller), may also prove to be a Glyptocrinus. The type specimens, 

 which Mr. Miller was kind enough to send us for comparison, are not in 

 a condition to make out the structure satisfactorily, being covered to a large 





Fig. 6. Reteocriniis Onealli. 



* Revision, Part HI., p. 88. 



