Crossword-Solution: METAZOAN 8 letters, 2 clues 🏆 scrabble score: 19

The derivation of all the Metazoa from a single ancestral form, the Gastræa, leads to the conclusion that the types are not distinct from one another as Cuvier and von Baer supposed, but agree in the one essential point, in the possession of an _archenteron_ (Lankester, 1875), and an ectoderm and endoderm which are homologous throughout all the Metazoan phyla.

There is thus a striking analogy, which has not escaped the philosophical biologist, between the ant colony and the cell colony which constitutes the body of a Metazoan animal; and many of the laws that control the cellular origin, development, growth, reproduction, and decay of the individual Metazoan, are seen to hold good also of the ant society regarded as an individual of a higher order.

The queen-mother of the ant colony displays the generalized potentialities of all the individuals, just as the Metazoan egg contains _in potentia_ all the other cells of the body.

And, continuing the analogy, we may say that since the different castes of the ant colony are morphologically specialized for the performance of different functions, they are truly comparable with the differentiated tissues of the Metazoan body.

Optional trip to museum for use of illustrative material to illustrate the principal characteristics of (_a_) a simple metazoan, sponge, or hydrazoan, (_b_) a segmented worm, (_c_) a crustacean (Decapod), (_d_) an insect, (_e_) a mollusk and echinoderm, (_f_) vertebrates.