Pl. zoa. Biol. [mod.L. (Herbert Spencer), a. Gr. ζῴον animal.] An organism scientifically regarded as a complete animal, i.e., one which is the total product of an impregnated ovum, whether constituting a single being as in the higher animals, or a number of distinct beings (zooids) as in the successive asexual generations of aphides or the various ‘persons’ that make up a compound or ‘colonial’ animal.
1864. H. Spencer, Princ. Biol., § 73. A zoological individual is constituted either by any such single animal as a mammal or bird, which may properly claim the title of a zoon, or by any such group of animals as the numerous Medusæ that have been developed from the same egg, which are to be severally distinguished as zooids.
