4.4.2 CLASS ECHINODERMATA. 
common on all our coasts, so much so, that in some places it 
is employed to manure the grounds. 
Ast. glacialis, L. Link. xxxviii. 69. Encyc. cvii. and cviii. 
is frequently more than a foot in diameter; the spines which 
invest the upper part of its body are surrounded with a mul- 
titude of little fleshy tubes, which form sorts of cushions 
around their bases. 
Ast. aurantiaca, L. Link. vi. vii. xxiii. Encyc. cx. Echin. 
pl. iv. 1., is our largest species. The edges of its branches 
are furnished with pieces, like mosaic work, on which some 
strong mobile spines are articulated. All the upper part is 
covered with some other small spines, terminating in truncated 
and bristling heads. 
Some have a number of rays above five. Their ceca and 
ovaries are very short. (Ast. paposa, Link.) 
We must separate from the other asteriz, the species in 
which the rays have no longitudinal furrows underneath, for 
the purpose of lodging the feet; in general, these rays are 
not hollow, and the stomach is not prolonged into cceca, but 
its prominences remain in their intervals. Locomotion is 
effected principally by the curving and the movement of the 
radii, and not by the feet, which are too few in number. 
M. de Lamarck names Ophiures those which have round 
a central disk five radii not branched. But we should still 
distinguish 
Those in which these radii are furnished on each side, with 
mobile spines. The small fleshy feet also issue forth on each 
side from between the basis of these spines. (Ast. nigra, 
Miill., &c.) 
And those in which the radii, having no lateral spines, but 
being furnished with imbricated scales, resemble the tails of 
serpents. The central disk, has, in each interval of the rays, 
on the side where the mouth is, four holes which penetrate 
into the interior, and serve, perhaps, for respiration, or, ac- 
