88 
PALAEONTOLOGY OF NEW-YORK. 
The surface of the Echino-encrinites is irregular, unequal, and embossed. The plates of the shell are 
convex, sub-pyramidal, and ornamented with thick and reticulated striae. These striae, always •perpen¬ 
dicular to the sides of the plate , as in the Echinosphaerites, form, by their combination in successive 
chevrons , five or six rhombs radiating from the centre of these. The union of these rhombs forms triangles 
inscribed one within the other where the plates are regular, or in part having a common base, when, by 
the reduction of the sides of a plate, one of the rhombs become rudimentary. The smallest of these 
triangles, comprised between three faces of the pyramid, corresponds with the angles of the plates of the 
shell. 
The Echino-encrinites is further distinguished by the presence of pores, not disseminated over the 
entire surface as in the Echinosphaerites, but occupying a determinate place, and bordering three small 
rhomboidal areas. These pores were only imperfectly defined by Schlotheim in his Echinosphaerites 
granatum , and by M. Herman von Meyer in his Echino-encrinites senkenbergii : it is to M. Vol- 
borth that we are indebted for having exactly marked their place (See Bull, de Saint-Petersbourg, 
Yol. x., no. 19, pi. 1, fig. 4, 5, 6 ). Two of these poriferous rhombs are situated near the base, and have 
their great diagonals united upon one of the angles of the opening where the stem is inserted; while the 
third is found on the opposite side, between the mouth and the great lateral opening, and directly above 
the pentagonal basal plate : the two first are mounted upon the plates of the two inferior ranges, and the 
last upon those, of the two superior ranges. 
What was the design of these pores, or elongated grooves, which bound the three rhomboidal areas ? 
It would, doubtless, be difficult to affirm any thing on this subject : it is sufficient to remark that these 
pores are disposed according to the same law as in the Echinosphaerites, or the Hemicosmites; that is to 
say, that they part from the centre of the plates, and unite at their angles. The middle of the rhomboidal 
areas are usually striated ; but the striae are less distinct than upon the rest of the crust, and appear some¬ 
times a little worn. The crust is in general solid, and crystallized in rhombohedrons as in all the crinoidea. 
The genus Echino-encrinites has been established by M. Herman Yon Meyer, in the Archives of 
Karstner, upon a specimen now unfortunately lost. The description and the figure which he gives of 
it are nevertheless exact enough to enable us to recognize, without hesitation, the fossil bodies of Saint- 
Petersburgh, confounded by MM. Pander and Bronn with the Echinosphaerites, and named by M. 
Eiciiwald Gonocriniies. M. df. Buch, struck with the impropriety of the name of M. Herman von 
Meyer, has proposed, in his Memoire of this year, to change it for that of Sycocystites. Although this 
name, it must be allowed, may be better than that which we have adopted, we prefer to follow the rule 
which we have imposed upon ourselves, to preserve always the most ancient names. 
The Echino-encrinites belong, as well as the Echinosphaerites, to the Lower Silurian system of 
Russia. M. Volborth, to whom we owe a notice upon those of the environs of Saint-Petersburgh, 
distinguishes three species of them in this country : the E. strialus, angulosus, and granatum. We 
possess only the two first of these, and we do not believe that the third species is identical with the 
Echinosphaerites granatum ( Wahl.), to which this author compares it. Indeed, according to M. de 
Buch, this last species, of which he makes the type of his genus Caryocystites, should have a very 
different number of plates, and the striae not reticulated. The Echino-encrinites senkenbergii ( H. von 
Meyer) constitutes probably a fourth species. M. Bronn, in his Leth/ta Geognostica, had reunited it 
to the Echinosphaerites granatum (Sciilot.); but in the additions and corrections of the same work, 
p. 1284, he says that M. Herman von Meyer has shown that this reunion has no foundation. 
The Echino-encrinites appear exclusively to belong to Russia; at least we do not know of their 
occurrence elsewhere. If the Cornulites serpularius is only a part of their stem, there is reason to believe, 
nevertheless, that they will be found in Gothland and in England, where this singular body has been 
discovered. ( Geology of Russia and the Ural Mountains, Vol. ii. pp. 27, 28 & 29.) 
