The gastrula stage was the palingenetic repetition of the ancestral form of all Metazoa, the Gastraea.
"Form and Function" by E. S. (Edward Stuart) Russell
How do protozoa differ from higher animals (metazoa) as regards (a) structure, (b) reproduction?
"Text Book of Biology, Part 1: Vertebrata" by H. G. Wells
The whole of the animal kingdom is divided into two great groups, which are called the Protozoa and the Metazoa.
"Darwin, and After Darwin (Vol. 1 and 3, of 3)" by George John Romanes
The parasites found in the bowel belong principally to two natural groups, Protozoa and Metazoa.
"Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 4" by Various
The phylum Porifera or Spongiae includes the simplest of the Metazoa or multicellular animals.
"Freshwater Sponges, Hydroids & Polyzoa" by Nelson Annandale
The Metazoa thus include Grades II., III., and IV.
"Stories of the Universe: Animal Life" by B. Lindsay
A considerable number of early developmental processes are common to the whole of the Metazoa.
"The Works of Francis Maitland Balfour, Volume 1" by Francis Maitland Balfour
The one-celled animals are called Protozoa, and the many-celled animals Metazoa.
"Elementary Zoology, Second Edition" by Vernon L. Kellogg