524 SUPPLEMENT 
This last type of the animal kingdom, we do not find de- 
signated under a collective name, except by the ancient and 
the most modern zoologists. ; 
Thus Aristotle, who appears, nevertheless, to have known 
some species of the principal classes which constitute it, has 
never employed the word zoophytes as a collective name or 
otherwise, although, in relation to the sponges, he has said, 
that they partake more of plants than of animals, and that it 
may be doubted whether they are animals or vegetables. 
But the compound word zoophytes, is not to be found in his 
works, though some authors have erroneously attributed it to 
him. 
It does not appear that he was acquainted with the ani- 
mals which are designated at present under the name of holo- 
thuria. He certainly employs this denomination, the etymo- 
logy of which is unknown; but he applies it to beings which 
have not the faculty of locomotion, though they are not at- 
tached any where, which leads us to presume, that by this 
word he indicated the actiniz, which, nevertheless, were de- 
signated by him under the name of acalephos, and which, in 
fact, he classes among the animals which partake at once of 
the animal and plant. 
Aristotle, on the contrary, was perfectly well acquainted 
with the echini and the asteriz, which he designates, the first 
under the name of sea-urchins, the second, under that of sea- 
stars. But he has made them animals of his division of tes- 
tacea; an approximation which we shall find to have been 
admitted, even to the end of the last century. He distinguishes 
several species very well, such as spatangus brissus, the 
sea urchins proper, and a smaller species. But still it does 
not seem that his distinction is established on characters 
sufficient to enable us to recognize at the present day, in any 
very certain manner, the animals of which he intended to 
speak. 
