Meek and Worthen on Paleozoic Crinoidea. 25 
ambulacral furrow, bearing the omen along its margins, on 
the outer side of the arms, an en the matrix is removed 
from these ambulacral furrow Ws, he arms can be seen to be 
composed each of a double series of small alternately-arranged 
pieces.. It is barely possible that in specimens of this species 
with the arms perfectly preserved, the ambulacral furrows may 
be covered on the outer or ventral side by a double series of 
alternating pieces, and that the tentacula* may connect wit 
little openings along each side, though there certainly appear 
to be only open furrows in the specimens examined. 
It is worthy of note, in this connection, that there certainly 
are species, agreeing exactly i in all other Known characters with 
this genus, that have no open furrow along the outer or ventral 
side of the arms, which are distinctly seen to be round on the 
outer side, and show there a double series of interiocking pieces 
along their entire length, while the tentacula connect along the 
inner, or under side, as the arms are seen hanging down. _ 
is clearly seen to be the case ina beautiful specimen of G. typ 
(=Trematocrinus typus Hall) in Mr. Wachsmuth’s ap thi 4 
and we can scarcely doubt that in this species there is an open 
furrow on the inner (under) or dorsal side of the arms. If not, 
the arms must be tubular, in consequence of having the ambu- 
lacral canal enclosed all around, excepting at the points where 
the tentacula connect along each side, 
3. Cyathocrinus Miller. Specimens of this genus oes. 
_ Price Pb na properly the ope Sant! have very rarely 
d a few exam ve been found, and chee 
hive beer supposed to show oe openings, one central and an- 
other lateral; the latter, according to Prof. Phillips’ and Mr. 
Austin’s fioures, being provided with a slender marginal tube, 
or so-called proboscis. Some of Mr. Wachsmuth’s specimens, 
however, of C. malvaceus and C. Iowensis Hall, showing the 
vault, have led us to doubt the existence of a central opening 
in the vault of this genus, when the specimens have this part 
entire. The specimen of (. malvaceus shows the remains of 
the usual narrow lateral proboscis, and also has an opening in 
-the middle of the vault, but from the appearance of this open- 
ing, as well as from the structure of the vault of a specimen 
of C. Iowensis, in which this opening is closed, we can scarcely 
doubt that it was also closed in the specimen of CO. m vaceus, 
when entire. The remaining parts of the vault of the C. mal- 
vaceus mentioned consist of only five comparatively large pieces, 
alternating with the upper inner edges of the first radial Pieces, 
* We use the term tentacula here in the sense of : Baga rn oo 
Of Crin 
-tologists, with reference to the delicate pinnule along the Prag: 
course not as applying to the minute fleshy mire 
usually termed tentacles by those who have investigated 4 recent ny aga 
