GENERAL OBSERVATIONS. 1029 



IT. Progress from the simple to the complex or the more specialized; 

 animal life, commencing with Protozoans, the simplest of species, without 

 special organs of any kind — Radiolarians, the minute, silica-secreting, 

 Ehizopod-like kinds, having been reported (1894) from rocks of Archeean 

 time — and becoming displayed in a few comprehensive structural types, 

 the simpler forms of which appeared in early time, and the more complex 

 successively afterward ; the new organs required in the highest manifesta- 

 tions of a type being only developments through modification of the older, 

 or better appliances evolved from the structure for carrying forward old 

 processes. 



III. The succession under a type parallel to some extent with the embry- 

 onic stages in related living species, part of the early life of the globe repre- 

 senting in some points the embryonic or young life of to-day. 



IV. Early types, often a combination of two or more types that were 

 afterward differentiated, that is, became separate, independent branches in 

 the sj^stem; synthetic types of Agassiz, comprehensive and generalized types 

 of others. 



V. The earlier species under a type often multiplicate in structure, and 

 losing this feature with rise in grade (pages 421, 437, 486). 



VI. The culmination of types, followed by degeneration, and often ex- 

 tinction, at various times along the successive eras, 



VII. In the degeneration of a type, often a partial return to some of its 

 early characteristics. 



VIII. The Animal kingdom, one in system from the beginning, — the 

 grander divisions of modern time being, to a large extent, those of the ear- 

 liest Paleozoic (page 486), and some Paleozoic genera still having their 

 species. The facts prove unity in system of life as well as in organic and 

 physical law. 



IX. A headward concentration or cephalization of the structure attend- 

 ing generally a rise in grade, and the reverse, or decephalization, a decline. 



X. The localization of tribes in time, or chronographically, involved in 

 the physical progress of the earth, that is, in its progressing climates, and 

 its conditions as to water and land. As now there are different zones, and 

 various localizations of species on going from the equator to the poles, so 

 there were necessarily successive phases and increasing diversity in the life 

 of the world on passing from the warm conditions and nearly universal seas 

 of early time to the present age of frigid polar regions and greatly differen- 

 tiated seas and lands. 



Evidence with reference to evolution hy vernation. — The propositions above 

 stated read like the heads in an argument for the evolution of the kingdoms 

 of life. They were so recognized many years before Darwin's first publica- 

 tion on this subject. Most of them were used by Agassiz in his lectures on 

 development, — by which he meant evolution; and evolution based on paleon- 



