Their
constitution, like that of the Ascidians, approximates them on one
side to plants, on the other to animals. For seeing that some of
them can detach themselves and can fasten upon their food, and that
they are sensible of objects which come in contact with them, they
must be considered to have an animal nature. The like conclusion
follows from their using the asperity of their bodies as a
protection against their enemies. But, on the other hand, they are
closely allied to plants, firstly by the imperfection of their
structure, secondly by their being able to attach themselves to the
rocks, which they do with great rapidity, and lastly by their having
no visible residuum notwithstanding that they possess a mouth.
Very similar again to the Acalephae are the Starfishes. For these
also fasten on their prey, and suck out its juices, and thus destroy a
vast number of oysters. At the same time they present a certain
resemblance to such of the animals we have described as the
Cephalopoda and Crustacea, inasmuch as they are free and unattached.
The same may also be said of the Testacea.
Such, then, is the structure of the parts that minister to nutrition
and which every animal must possess. But besides these organs it is
quite plain that in every animal there must be some part or other
which shall be analogous to what in sanguineous animals is the
presiding seat of sensation.
Pages:
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193