436 FOURTH GRAND DIVISION. 
holothuriz have two vascular apparatus ; one attached to the 
intestines, and corresponding to the organs of respiration ; 
the other serving only to fill the organs which occupy the 
place of feet. This last alone is distinctly seen in the echini 
and asteriz. We can see through the gelatinous substance of 
the medusz, some canals, more or less complicated, which pro- 
ceed from the intestinal cavity. All this indicates no possi- 
bility of a general circulation ; and in the great majority of 
zoophytes, it is easy to convince one’s self that there are no 
vessels of any kind. 
Some genera, such as the holothurie, the echini, and seve- 
ral intestinal worms, have a mouth, and an anus, with a dis- 
tinct intestinal canal; others have an intestinal sac, but with 
only a single opening, representing both mouth and anus. 
In the greater number, there is nothing but a cavity, hollowed 
in the substance itself of the body, which sometimes opens by 
several suckers. Finally, there are many in which no mouth 
is perceptible, and which can only be, nourished by the 
absorption of their pores. 
The distinction of sex is observable in several intestinal 
worms. ‘The greater number of the other zoophytes are her- 
maphrodite and oviparous; many have no genital organs, and 
are reproduced by buds, or by division. 
The composite animals, of which we have already observed 
some traces among the last of the mollusca, are greatly mul- 
tiplied in certain orders of the zoophytes, and their aggrega- 
tions form trunks and expansions of every sort of figure. This 
circumstance, united to the simplicity of organization in the 
majority of species, and to that radiating disposition of the 
organs, which reminds us of the petals of plants, has obtained 
for them the name of zoophytes or animal plants, by which 
these apparent relations only are meant to be indicated ; for 
the zoophytes, possessing sensibility, voluntary motion, and 
nourished for the most part, on matters which they swallow, 
