External Structure of Paleozoic Crinoids. 381 
ceeded in distinguishing cilia on the surface which forms the 
floor of these furrows, yet I have distinctly seen such a rapid 
passage of minute particles along their groove as I could not 
account for in any other mode, and I am therefore disposed to 
believe in their existence. Such a powerful indraught, more- 
over, must be produced, about the regions of the mouth, by the 
action of the large cilia which fringe various parts of the in- 
ternal wall of the alimentary canal, as would materially aid in 
the transmission of minute particles along those portions of 
the ambulacral furrows which immediately lead toward it; and 
itis, I feel satisfied, by the conjoint agency of these two moving 
powers that the alimentation of Anéedon is ordinarily effected.” 
It appears from these observations that the mouth of Ante- 
don has no special functions as such, but is merely a receiving 
centre or general passage, into which the food which acci- 
dentally falls into contact with the furrows of the arms or pin- 
nul enters—a passage which might as well be external, 
hidden beneath a vault, as open to the surrounding element, 
provided the food could be brought into contact with it. The 
large cilia on the inner wall of the alimentary canal, which 
Dr. Carpenter describes as being capable of producing such a 
powerful indraught to the region of the mouth, afford, it seems 
to me, also a very satisfactory explanation of the mode by 
which the transmission of food was effected in Paleozoic Cri- 
noids. How much more powerful must have been the effects 
of these cilia in individuals in-which mouth and furrow were 
arched over and in which the current was unobstructed from 
without! Considering, further, that probably the covered 
parts of the food-channels themselves were fringed with cilia 
of similar functions, it could have been of but little moment 
how remote from the mouth the food entered. We find another 
most striking example in confirmation of this supposition in 
Hypomene Sarst, Lovén, a recent Cystidean, indicating, in 
analogy with recent nature, that Crinoids had the mouth some- 
times internal. Prof. Lovén found in the covered parts of its 
channels microscopic Crustacea, larval bivalves, and other re- 
mains of the food of the animal, apparently taken through the 
open parts of the channels. Applying this observation to 
Paleeozoic Crinoids, it seems very probable that their food was 
taken up along the open parts of the arms or pinnule, and 
conveyed through the closed parts to the concealed mouth. 
Dr. Ludwig Schultze, in his excellent ‘ Monograph on the 
Echinoderms of the Eifel’ (Vienna, 1867), was, so far as I 
know, the first author who suggested the idea that all Cri- 
noids which are covered on their ventral side by solid plates, 
and have but one orifice, were provided with an internal 
