440 CLASS ECHINODERMATA. 
terminate them, that these animals execute their progressive 
movements. Some vessels proceeding from these little feet, 
repair to the trunks, which correspond to their ranges, and 
which end at the mouth. ‘They form a system distinct from 
that of the intestinal vessels which are observed in some 
species, 
Linnzus makes of these animals three genera, very natural, 
but sufficiently numerous, and comprehending species suffi- 
ciently varied to be considered as three families. 
ASTERIAS, L. Vulg6, Sea-stars, or Star-fish. 
Have received this name, because their body is divided into 
radii, most frequently five in number, at the centre of which, 
underneath, is the mouth, which at the same time serves 
as anus. 
The frame-work of their body is composed of small osseous 
pieces, variously combined, the arrangement of which would 
merit investigation, They have a very great power of repro- 
duction, and not only reproduce the radii, which have been 
taken away separately, but a single ray with the centre being 
preserved can reproduce the others, which is the cause that 
we so frequently find them irregular. 
In the 
ASTERIAS, Lam., 
Or Asterias, properly so called, each ray has, underneath, a 
longitudinal furrow, on the sides of which are pierced all the 
little holes which allow the feet to pass. The rest of the in- 
ferior surface is provided with small mobile spines; the entire 
surface is also pierced with pores, which allow some tubes 
much smaller than the feet to pass, which probably serve to 
absorb the water, and to introduce it into the general cavity 
for a kind of respiration. On the middle of the body, a little 
towards the side, is a small stony plate, to which corresponds 
