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the joints is at the exterior circumference angularly truncated, so that a penta- 

 gonal circumference is formed, the sides of which are slightly excavated. On 

 each of the sides of the angle arising from the truncation of the joints of the 

 pelvis, at the exterior surface, a transverse ridge with a central perforation may 

 be traced, which unites with that from the neighbouring joint, and thus offers 

 a firm articulation in each of the five excavated spaces for one of the first costal 

 joints, which gain further support by resting against the column where they 

 occasion the impression noticed before. 



I have no hesitation in saying that this animal when perfect must have borne 

 considerable resemblance to Encrinites moniliformis ; yet it appears to be suf- 

 ficiently distinguished from that genus by the enlarged first columnar joint, 

 and the firm adhesion and growing together of the pelvis with it. It is this 

 latter circumstance which at once accounts for the columnar joint never occur- 

 ring without the pelvis. 



I cannot, however, omit to suggest a conjecture concerning these specimens, 

 which has occurred to me as probable, with regard to the anchylosing of the 

 pelvis to the column. The Crinoidea in an early stage of growth, as I have shown 

 when speaking of Pentacrinus caput medusae, do not display the different joints 

 of which they are composed in so distinct and well marked a manner as on 

 mature age ; the calcareous matter forming their nucleus has not yet been 

 secreted in sufficient quantity, and remains so involved with the membranous 

 parts, as often to render it impossible to determine the line of separation 

 between one joint and the other. Now the specimens ofEuoENiA CRINITES quin- 

 quangularis, occur only of a very small size ; and I have before alluded to the 

 marks of original cartilaginous consistency exhibited by one in my possession. 

 Should then these remains be those of young animals, in which an insufficient 

 calcareous secretion has not as yet distinctly separated the plates, they might 

 very possibly assume the regular character of the germs Encrinites in a more 

 advanced stage of their growth. Of course in this case it would become neces- 

 sary to suppress this genus, and incorporate it in that indicated. 



