TRENTON LIMESTONE. 87 
Genus ECHINO-ENCRINITES. 
Echino-encrinites, HERMAN Von Meyer, 1826. Kanrstner, Archiv. fur die Naturlehre, Vol. vii. p. 185 - 
192, pl. 2, fig. 1-5; Vol. viii. p. 232 — 237. 
Echinospherites, PANDER, 1830, Sp. Bronn, 1835, Sp. 
Goniocrinites, Ercu wap, 1840. 
Echino-encrinus, VouBortH, 1842. 
Sycocystites, Von Bucn, 1844. 
This genus is one among the few which Vow Bucu has included in his family Cystipra, 
a group intermediate between the Ecuinipea and the true CrinorpEa, and which pass into 
the latter by the genus Caryocrinus, which combines in some degree the characters of 
both groups. 
The discovery of a species of this genus among the fossils of our older strata furnishes 
another interesting link, connecting in their paleozoic characters the rocks of the European 
continent with those of America, and showing that at so early a period, when the peculiar 
forms of Ecninopermata, the CrinoipeA, flourished in considerable numbers, a genus also 
existed which indicated a structure intermediate between that then numerous family, and 
the future EcuinipEa, a portion of this great group being at the same geological period 
represented by a true ASTERIAS. 
The following extract, translated from the observations upon this genus in the second 
volume of the Geology of Russia and the Ural Mountains, will convey a more definite idea 
than my own language ; since, thus far, I have had no opportunity of examining any other 
than very imperfect specimens. 
This easily characterized genus belongs, as well as the Ecutnospnarires, to the Crinoidea with 
closed summits and destitute of arms, or the Cystidea of M. pz Bucn; but it is distinguished from the 
first, by the small number of its plates, their form and their regular arrangement. We find in them, 
indeed, only four basal plates, ten intermediate plates forming two ranges of five each, and five superior 
plates which unite at the summit. Of the four basal plates, three are quadrangular, and the fourth becomes 
pentagonal by the truncation of its salient angle. This last is exactly opposite to the two poriferous 
rhombic plates, of which we shall speak immediately ; and upon its truncated side is placed one of the 
plates which extends to the great lateral circular aperture, and which helps to form its contour. This 
opening is free, without enclosing plates ; and as this is the only one, except the mouth, which we discover 
on the surface of these bodies, it is very probable that it served both as the anus and as an ovarian 
aperture. M. VotBortu supposes that it was divided in the interior, to serve this double function It is 
certain that we see on none of our specimens the convex and pentagonal star, which is always remarked 
on the Echinospharites. 
Another very important character of the Ecu1No-ENcRINITES, is their being provided with a thick, 
round, creuse, elastic and contractile stem, which, by its thickness, contrasts with the small, and still so 
little known stem, of the other genera of the group Cystidea. This stem is not articulated like those of 
the Encrinites, and appears to be composed of tubes resting one within the other, and graduated like the 
compartments of a spyglass : it is besides covered with longitudinal striz, and appears to us, as also to 
M. VoxtsortTn, very analogous to, if not identical with, the Cornulites serpularius of authors.* 
* See fig. 3, p. 89. 
