139 
Cyathocrinites, which I hesitated to point out before I had proved the non- 
existence of the column in Marsupites, If we consider the lower pentangular 
plate in this genus (which i is similar in position to that in Comatula) to serve 
in both as a keystone to their vaulted cup, or as a plate performing in part the 
office of a first columnar joint, (since the other plates adhere to its edges) and 
thus apply the anatomical nomenclature used when describing the Cyatho- 
crinites, we shall find the five plates forming the pelvis in that genus truly 
conformable to the five costals in Marsupites, differing only in their upper 
edges being bent, to formas its were a concave rim, and the lower surface 
being excavated to give articulation to the column. The Bye intercostal plates 
in Marsupites correspond in figure and marking with the five costals in 
Cyathocrinites, and the scapule, integument, and commencement of the arms 
exhibit a conformity conspicuous at first sight. It is truly pleasing by 
this change of anatomical momenclature, to point out in a more striking 
manner the method in which nature effects the transition from one being to 
another. Inthe Comatula, the absence of the column showed the first link 
from the Crinoidea articulata to the Stelleridz, in the Marsupite a similar link 
is offered from the Crinoidea inarticulata to that family. 
