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the second costal joint of Pentacrinus caput medusas in general figure, yet here 

 the first costal joint is externally so much overlaid by the second, that it is only 

 visible at its lateral margins. 



The SCAPULA resemble also those of that Pentacrinite, but are much more 

 angularly pointed at their superior surface, and are also tied laterally together 

 by an integument. 



From each of the scapulae in the different species proceed either two arm- 

 like fingers, or two arms ; each of the latter formed of a common and cunei- 

 form joint, from which, on one side the first finger, and on the other side a con- 

 tinuation of the arm sets off, which, again, by the intervention of cuneiform 

 joints, divides into two or more fingers, and thus forms a hand like in other 

 Crinoidea. Each joint of the arms and fingers sends off from alternate sides a 

 tentaculum formed of many articulated small joints, resembling in formation 

 those of Pentacrinus caput medusas. 



An integument extends over the abdominal cavity, the groove in the arms, 

 fingers, and tentacula, and is, like that in Pentacrinus, also protected by 

 numerous minute calcareous plates. In some species of Comatulas, this integu- 

 ment extends laterally in a fimbriated manner, connecting the tentacula, and 

 sometimes portions of the arms and fingers near their origin, together. In these 

 cases the integument is here excessively thin and transparent, having at the 

 margin of its fimbrise a few minute plates probably to add to its strength. I 

 apprehend that this lateral extension of the integument may probably have 

 existed in some of the Crinoidea, but it is almost impossible that we should 

 expect to detect so fine a membrane in a fossil state ; should it however, 

 favoured by peculiar circumstances, ultimately be detected, I feel confident it 

 would furnish a good specific character, and perhaps lead to the distinction of 

 species at present apparently similar. 



An insufficient supply of specimens, and want of opportunity to examine dif- 

 ferent species, hasprevented me from ascertaining whether the groove in the 

 arms and fingers extends also along the tentacula. In the fimbriated Comatulae 

 I should apprehend it does not, since each of the joints forming the tentaculum 

 in those which I have seen has only a concave impression near the base, where the 

 fimbria is attached more firmly than above this depression. Hence I appre- 



