151 
the second costal joint of Pentacrinus caput meduse 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 ScAPULZE 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 scapule 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 meduse, ⁄ 
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 Comatule, 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 fimbrie 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, 1 feel confident it 
would furnish a good specific character, and perhaps lead to the distinction of 
species at present apparentl y similar. . 
An insufficient supply ofspecimens, 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 Comatulz 
I should apprehend it does not, since each of the joints forming the tentaculum 
in those which 1 have seen has only 8 concave impression near the base, where the 
fimbria is attached more firmly than above this depression, Hence 1 appre- 
