SUPPLEMENT 
ON THE 
FIRST CLASS OF ZOOPHYTES. 
THE ECHINODERMATA. 
THIS term was invented by Klein, and applied by him with 
sufficient exactitude, as he only comprehended under this 
name the echini of Linneus, (echinites, Lam.) all of which 
have the skin covered with hard prickles, varying somewhat 
in form, which has caused them to be compared to hedge-hogs. 
But Bruguiéres, by uniting under this name the asteriz to 
the echini, has certainly not proved so correct in nomencla- 
ture, inasmuch as none of the latter present any traces of 
prickles on the surface of the skin. M. Lamarck, and the 
authors who have followed him, have rendered this name still 
more equivocal by including under it the holothurie, and 
even the sipunculi, which may be considered almost as ge- 
nuine worms. M. de Blainville has restrained this name to 
the three orders, holothuriz, echinites, and asterias ; but is yet 
of opinion, that the name of placyrodermata, would better 
distinguish them, as indicating the principal character which 
they present, which is the existence of a great number of ten< 
tacular and respiratory suckers, by means of which the animal 
performs the function of locomotion. 
