130 THE HISTORY OF CREATION. 



developed into the PTothelmis, the common primary form 

 of Worms (Vermes). (Compare p. 133.) 



This latter tribe (as limited by modern zoology) is of the 

 greatest interest in the study of genealogy. For among 

 Worms, as we shall see later, there are, besides very nume- 

 rous peculiar families, and besides many independent 

 classes, also very remarkable forms, which may be con- 

 sidered as forrns of direct transition to the four higher 

 animal tribes. Both comparative anatomy and the on- 

 togeny of these worms enable us to recognize in them 

 the nearest blood relations of those extinct animal forms 

 which were the original primary forms of the four higher 

 animal tribes. Hence these latter, the Molluscs, Star-fishes, 

 Articulated animals, and Vertebrate animals, do not stand 

 in any close blood relationship to one another, but have 

 originated independently in four different places out of the 

 tribe of Worms. 



In this way comparative anatomy and phylogeny lead us 

 to the monophyletic pedigree of the aninnal kingdom, the 

 outlines of which are given on p. 133. According to it the 

 seven phyla, or tribes, of the animal kingdom are of different 

 value in regard to genealogy. The original primary group 

 of the whole animal kingdom is formed by the Primaeval 

 animals (Protozoa), including the Infusoria and Gastrseads. 

 Out of these latter arose the two tribes of Animal-plants 

 (Zoophyta) and Worms as diverging branches. Out of four 

 different groups of the Worm tribe, the four higher tribes 

 of the animal kingdom were developed — the Star-fishes 

 (Echinoderma) and Insects (Arthropoda) on the one hand, 

 and the Molluscs (MoUusca) and Vertebrated animals 

 (Vertebrata) on the other. 



