‘THEIR LIFE AND AFFINITY. ~ F 94S 
under the influence of light; wherefore, though sometimes fettered to 
the earth, it is by no means fixed or rooted in it, to which cireum- 
stance it owes its faculty of locomotion. 
A further consequence which flows from the above consideration is, 
that the animal cannot, like the plant, draw its nourishing juices from 
the soil, because its whole organism has a tendency to inward unity; its 
very root-organs are turned inwards and formed into intestines; from 
which we are able to show most evidently the origin of the excretory 
canal and of the absorbent and circulating vessels. Let us suppose 
for instance a plant A, living with the atmospheric part + above- 
ground, and with its terrestrial part — underground; let us now detach 
it from the ground so that all the fibres of its root, a bcc, having 
struck back into the internal parts of the stem and of the leaves, may 
be reversed inwards; we shall then have the figure B, in which the part 
subjected to the light perfectly encompasses that subjected to the earth; 
and ab appears as the alimentary duct; 0, as the cavity of the stomach, 
and ¢ ¢ as the vessels for distributing the sap. 
Here we observe how very much in this metamorphosis the plant has 
assumed the type of the animal body, such as we observe it among the 
lower classes of animals. In this way we may now see why in the Medusa, 
the Sea-star, the Echinus, and other inferior kinds of animals, the aperture 
of the mouth is turned downwards, and the alimentary duct upwards* ; 
or in this way we may see that the lower classes want the opposite or pos- 
terior opening of the excretory ducts (anus), or that (as is likewise par- 
ticularly evident in the Medusa+) the vascular organs branch out imme- 
‘diately from the cavity of the stomach, and that the leaf-formed parts 
'B, a@ a, furnish an explanation of the appearance of a kind of exter- 
* Carus, Lehrbuch der Zootomie, p.327. . + Ibid., p. 578. 
