ORDER PEDICELLATA. 441 
internally, a canal filled with calcareous matter, which is 
believed to contribute to the growth of the solid parts. In- 
ternally, is seen a large stomach immediately upon the mouth, 
from which proceed, for each ray, two cceca, ramified like 
trees, and each suspended to a sort of mesentery. There are 
also two ovaries in each ray, and it appears that the asterie 
fecundate themselves. A peculiar vascular system corres- 
ponds to their intestine, and there is another for the feet. 
M. Tiedemann considers as their nervous system, a very 
fine filament which surrounds the mouth, and sends a branch 
to each arm, which proceeds externally between the feet, and 
gives forth two ramuscula internally. 
Their osseous frame-work consists principally, for each 
branch, in a sort of column predominating along the inferior 
face, composed of vertebre, articulated one with the other, 
and from which proceed the cartilaginous branches, which 
support the external envelope. Between the roots of these 
branches are the holes through which the feet pass. Other 
osseous pieces, to which mobile spines are frequently attached, 
furnish, in many species, the lateral edges of the branches. 
Certain asteriz have the form of a pentagon, with rectili- 
near sides, rather than that of astar. The radiation is marked 
externally only by the sulcus of the feet. (Asterias dis- 
coidea, Lam.) 
Others have, on each side of the pentagon, a slight re- 
entrant angle. (Asterias membranacea, Link.) 
In others, the sides are concave, which begins to give them 
the figure of a star. (Asterias tessalata, Lam., &c.) 
In these different species, the coeca and the ovaries are not 
as much elongated as in the majority of the others, which 
have their radii elongated, and separated by well marked 
re-entrant angles. 
Such are 
Ast. rubens, L. Encyc. cxili. 1, 2. which is exceedingly 
