BioConcepts

bilateriaBilateria (ger.)

• The subkingdom that contains all animals (kingdom Animalia) possessing bilateral symmetry and three embryonic germ layers (the cells that will develop into the organs of the body). It is the largest animal subkingdom. (Oxford Dict. of Earth Sciences 2008)
  category morphology

  1874

  the group of Metazoa divided again into two sub-groups, first the Zoophyta (or Cœlenterata), which, in consequence of their habits in life, form the so-called radiate type; and, secondly, the Bilateria (or Sphenota), which, in consequence of their crawling habits of life, form the so-called “bilateral type.” Among the Bilateria, the lower worms (Acœlomi) agree with the Zoophyta in the want of the cœlom (body-cavity), and of a circulatory system; and then, again, from these primary older acoelomatous worms the higher worms (Cœlomati) have secondly developed themselves by the formation of a cœlom and of a circulatory system (depending thereon). Four divergent descendants of the cœlomatous worms form the four typical most highly developed races of animals: the animal stems or phylae of the Mollusca, Echinodermata, Arthropoda, and Vertebrata.

  Haeckel, E. (1874). The Gastraea-theory, the phylogenetic classification of the animal kingdom and the homology of the germ-lamellæ (transl. by E.P. Wright). Quarterly Journal of Microscopical Science 14, 142-165: 150-1.

  1874

  wir [können] die sämmtlichen, ursprünglich bilateralen Descendenten der Gastraea (die Abkömmlinge der Prothelmis) in eine natürliche Hauptabtheilung zusammenfassen, welche wir kurz Bilateria oder Sphenota („Keilthiere“, wegen der keilartigen Grundform im Sinne Bronn’s) nennen wollen. Diese Gruppe umfasst sämmtliche Würmer und die davon abzuleitenden vier höchsten Thierstämme: Mollusken, Echinodermen, Arthropoden, Vertebraten).

  Haeckel. E. (1874). Die Gastraea-Theorie, die phylogenetische Classification des Thierreichs und die Homologie der Keimblätter. Jena. Z. Naturwiss. 8, 1-55: 33.