from The Century Dictionary.
- noun The fact or the doctrine of the origination of living beings and the formation of their parts or organs. Also
from the GNU version of the Collaborative International Dictionary of English.
- noun The doctrine of the formation of living beings.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun zoology The doctrine of the formation of living beings.
from Wiktionary, Creative Commons Attribution/Share-Alike License
But he still holds fast to the main thesis of transcendentalism -- the absolute unity of plan of all animals, vertebrate and invertebrate alike,  the gradual perfecting of organisation from monad to man, the repetition in the embryogeny of the higher animals of the "zoogeny" of the lower.