338 BIOLOGY AND ITS MAKERS 
O. C. Marsh (Fig. ror) is noteworthy for similar explora- 
tions; his discovery of toothed birds in the Western rocks 
and his collection of fossil horses, until recently the most com- 
plete one in existence, are all very well known. Throughout 
his long life he contributed from his own private fortune, and 
intellectually through his indefatigable labors, to the progress 
of paleontology. 
Zittel—The name most widely known in paleontology 
is that of the late Karl von Zittel (1839-1904), who devoted 
all his working life to the advancement of the science of fos- 
sils. In his great work, Handbuch der Palaeontologie (1876- 
1893), he brought under one view the entire range of fossils 
from the protozoa up to the mammals. Osborn says: “It 
is probably not an exaggeration to say that he did more for 
the promotion and diffusion of paleontology than any other 
single man who lived during the nineteenth century. While 
not gifted with genius, he possessed extraordinary judg- 
ment, critical capacity, and untiring industry.” His portrait 
(Fig. 102) shows a face ‘full of keen intelligence and enthu- 
siasm.”” 
Zittel’s influence was exerted not only through his writ- 
ings, but also through his lectures and the stimulus imparted 
to the large number of young men who were attracted to 
Munich to study under his direction. These disciples are 
now distributed in various universities in Europe and the 
United States, and are there carrying forward the work begun 
by Zittel. The great collection of fossils which he left at 
Munich contains illustrations of the whole story of the evolu- 
tion of life through geological ages. 
Recent Developments.—The greatest advance now being 
made in the study of fossil vertebrate life consists in establish- 
ing the lineage of families, orders, and classes. Investigators 
have been especially fortunate in working out the direct line 
of descent of a number of living mammals. Fossils have 
