60 UINTACRIXUS: ITS STRUCTURE AND RELATIONS. 



Measures, as I have a specimen of Ichthyocr'ums, or some closely allied 

 genus, from those beds in Kansas, — which brings the Impinnata somewhat 

 nearer geologically to the Liassic ComatuliB than was before known. 



Wherever it may belong, and whatever its line of descent, there is no 

 doubt that Uintacrinus is both a protean and convergent form more remark- 

 able than any we have hitherto encountered among the Crinoids. Along 

 with great variability and instability in the base and interbrachial regions, 

 it combines : — 



The interbrachial system and fixed pinnules of the Camerata, 



The pliant test of the Flexibilia. 



The large viscei-al cavity of both these. 



The exocyclic disk and open ambulacra, and the arms, pinnules, and 

 syzygies of Actinometra. 



The free-floating character of the ComatuliB. 



The dicyclic base of the Dicyclica. 



The monocyclic base of the Monocyclica. 



SPECIFIC RELATIONS OF SPECIMENS FROM LOCALITY NO. 2. 



The colony of small specimens found at Locality No. 2 is a very inter- 

 esting occurrence. As already stated, the principal material secured 

 therefrom is the fine slab in the Kansas University Museum at Law- 

 rence. Through the courtesy of Chancellor F. H. Snow, and Dr. S. W. 

 Williston, of that institution, I have had full liberty to examine and study 

 this material, and, in addition to this, I am indebted to them for some 

 well-preserved specimens of this form for the illustration of this paper. I 

 acknowledge my deep obligation to these gentlemen for the aids thus 

 generously afforded me. 



Only a portion of the colony was recovered, the greater part of it having 

 been destroyed with the erosion of the ravine. As flattened out in the 

 fossil state, it was evidently about eight feet in diameter, and the specimens 

 were massed together and consolidated into a thin plate, as at Locality No. 1. 

 In the portion preserved there are about 550 calices visible on the lower 



