: 
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Re Oe eee pif aia ae oe 4 
Meek and Worthen on Paleozoic Crinoidea. 33 
separated by deep furrows on the outer side. In Strotocrinus, 
the vault of which is greatly expanded laterally, and often flat 
on top, these internal furrows, in radiating outward, soon be- 
come separated by partitions, ‘and as they ¢ go on bifurcating, to 
send a branch to each arm, they actually assume the character 
of rounded tubular canals, some distance before they reach the 
arm-bases. 
That these furrows or passages of the inner side of the vault 
were actually occupied during the life of the animal by the 
ambulacral canals as they radiate from the top of the convo- 
luted digestive sack to the arm-openings, we think no one will’ 
for a moment question, after examining Mr. Wachsmuth’s spe- 
cimen of Actinocrinus proboscidialis, which we have described, 
showing all these parts in place. It is also worthy of note, 
that in all the specimens of various types in which these fur- 
rows of the under side of the vault are well known, whether 
from detached vaults, or from casts of the interior of ‘the same, 
they never converge directly to the Stir of the vault, but to 
a point on the anterior side of it, whether there is a simple 
CRONE or a produced proboscis. The point to which they con- 
verge, even in types with a decidedly lateral opening of the 
vault, is ‘eave central or very nearly so, and even when the open- 
ing is nearly or quite central, the furrows seem to go, as it were, 
out of their way to avoid it, ‘those from the posterior rays pass- 
ing around on each side of it to the point of convergence of 
the others, a little in advance of the o Teg That the ambu- 
in tint at one of these specimens, special 
internal cast of the vault, ae the furrows (or cate of hora) 
_ starting from a central, or nearly central ures and radiating 
and bifurcating so as to send a branch to each arm-bas e, while 
_ the opening or ' proboscis of the vault (or the protuberance re- 
_ presenting it in the cast) is seen to occupy a position some- 
_ where on a line between this central point from which the fur- 
_ rows radiate, and the posterior side, one can scarcely avoid 
being struck ‘with the fact, that this point of convergence of 
the ambulacra, under the vault, bears the same relations in 
- position to the opening of the vault, that the mouth of a Coma- 
tula does to its anal opening. And when we remember that 
_ eminent authorities, who have dissected specimens of the exist-— 
ing genus Comatula, maintain that these animals subsisted on 
genes organisms floating in the sea-water, such as the © 
uR. Sct.—Szconp Series, Vou, XLVIL, No. 142.—Jvuzy, 1869. 
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