~ Von Buch on Crinoidea. 13 
from the petiole, and in Echinus and the allied genera there 
is no longer need of any corolla. 
But before the ocean-lily had opened and expanded its 
arms, it moved on a short pedicel in the closed state in innu- 
merable quantity, and only by frequent and highly varied at- 
tempts did this rupture and expansion succeed. These closed 
Crinoidea are still but little and imperfectly known; they 
deserve to be known, however, in every respect. For hitherto 
no Encrinus has been found in the lower beds, and from 
them there is formed an uninterrupted transition to the 
Pentacrinus of the existing ocean. Hitherto these forms have 
occurred almost exclusively in northern countries; in Sweden, 
in Norway, and in the hills which bound St. Petersburgh on 
the south; and among them the Spheronites are most fre- 
quently met with. 
These are large round spheres, like oranges, with two poles 
at the extremities. Linnzus, in his journey through Oeland, 
called them crystal-apples. Gyllenhahl, in an able investiga- 
tion and description (1772), was however the first to recog- 
nize their organic nature, and concluded that they might be 
placed near to Echinus, on which account Wahlenberg ap- 
plied to them the name Echinospherites, which Hisinger 
has exchanged for the better one of Spheronites. These 
spheres are formed of numerous polyhedrous plates, gene- 
rally hexagonal, perhaps of two hundred in one specimen. 
Above opens a mouth, which is covered by a number of very 
small moveable shields. Below, a petiole of thin pentagonal 
articulations fixes the body to the soil. The plates are all per- 
forated. In Spheronites Aurantium these small pores stand in 
a row from each angle of the polyhedron towards the centre, 
yet not quite up to the centre itself. Hach of these pores is 
connected by a deep furrow with the adjacent plate, thus gi- 
ving rise to rhombs, which always extend over two plates or 
assule; sometimes so prominently, that the rhombs them- 
selves have been taken for assule, and a species erroneously 
named Spheronites Granatum, because a similarity was found 
in these rhombs to the surfaces of a granite crystal. But 
Gyllenhahl had long before shown that the true polyhedrous 
assulze bisect the rhombs in the shorter diagonal, and at right 
angles with their striping. Pander, however, proves what had 
escaped Gyllenhahl, that these stripes or grooves connect ten- 
tacular apertures, as two pores do in the ambulacra of the 
species of Cidaris. And therefore it is very probable that 
Ischadites Koenigit (Murch. ‘Silur. Syst. Pl. 26. fig. 11.) is 
only Spheronites Aurantium, upon which an outline has been 
given to the rhombs not belonging to them, and distorting 
the whole. This discovery of Pander of tentacular passages, 
