874 FB soi eae of the Illinois Geological Report. 
through a more or less ere tube, we regard as the anal 
aperture, as in the existing crinoids; and not the mouth, or 
both mouth and anus, as believed by some.* The only differ- 
ence, therefore, as we understand the facts, is that, in the recent 
types, the ambulacral canals and mouth are directly exposed 
externally, the former merely passing to the latter across the 
upper surface of a membranaceous ventral integument; while, 
in the ancient crinoids, the whole ventral ioornits — ting the 
anal opening), as well as the ambulacral canal 3 outh, 
was very generally, if not oe covered over by a vault of 
fixed, so es calcareous piece 
That some of the most Sictiupruiched naturalists of Hurope, 
including Peofeasot Wyville Thomson, of Belfast, the lamented 
rof. Michae. Sars, of Christiania, and others, to whom we 
. several years back sent photographs of plates 1x and XvI, sub- 
— concurred with us in the ne: interpretation of 
e facts presented by the specimens illustrated on the same, 
we have been assured, both by private letters from these gentle- 
men, and in some instances by their publications.+ 
It is proper, however, to state here, that Mr. Billings, the 
very able paleontologist of the Canadian Geological Survey, 
who is one of the highest authorities on the Paleozoic crinoids, 
dissents from these views, and maintains, with much ability, that 
the single opening in the vault of these old types performed bot 
oral and anal functions; or, in other words, t that the mouth, 
unlike <a 2 the existing crinoids, was, in the former, remove 
from the center of radiation, and rac pro from all direct 
connection with the ambulacral system. 
Codonites stelliformés, figures 5 and 5a, b,—In connection with 
the foot-note on page 464, in regard to the parts described by 
. oo the single opening seen in the vault of these ancient crinoids could not 
rformed both oral and anal functions, at least in Platycrinites, seems & 
eich rc d, by the fact that we often find (as mentioned on pages 334 to 339 
ature and illustrated by Pare 6a, b, ¢, of plate Xv1) specimens past the shell 
ing that it Ae sihbcs during the the ant od the crinoid. In these cases, we can 
und d s droppings of the paren may 
out under the foot of the mollu ae Wak ia it would be exceedingly difficult to fo explain 
how food could have passed in under such presage nt 
iff 
° 
® 
® 
3: 
2 
ge 
In j to Dr. L. Shultze, of Bonn, I avail myse s opportunity 0 
att attention-to the fact, that he had, in hi ios of the Echino- 
ata of the Eifel limestone, published in 1866, exp: ery similar views 
in regard to the internal position of the por. and the mode of alimentation, 2 
the sortie crinoids ; (Bes the specimens at his command for ware! were far 
tory ee d by us re believed 
oa 
At the time we first published our remarks on this subject, in 1868, we had = 
seen | had n no knowledge of the fact that he had ever expressed simi 1 
views, or we certainly have mentioned it. I regret that I have not his 
Monograph ut hand nov, eo that I eould quote his words, or refer more Pp 
to the pages on which they occur. 
