of evolution. The American
palaeontologists in particular--Cope, Hyatt, Ryder, Dall, Packard,
Osborn--have worked out a complete neo-Lamarckian theory based upon the
fossil record.

The functional point of view was well to the fore in the works of those
great palaeontologists, L. Ruetimeyer (1825-1895) and V. O. Kowalevsky
(1842-83), who seem to have carried on the splendid tradition of Cuvier.
Speaking of Kowalevsky's classical memoir, _Versuch einer natuerlichen
Classification der fossilen Hufthiere_, Osborn[552] writes:--"This work is
a model union of the detailed study of form and function with theory and
the working hypothesis. It regards the fossil not as a petrified
skeleton, but as having belonged to a moving and feeding animal; every
joint and facet has a meaning, each cusp a certain significance. Rising
to the philosophy of the matter, it brings the mechanical perfection and
adaptiveness of different types into relation with environment, with
changes of herbage, with the introduction of grass. In this survey of
competition it speculates upon the causes of the rise, spread, and
extinction of each animal group. In other words, the fossil quadrupeds
are treated _biologically_--so far as is possible in the obscurity of
the past" (p. 8). The same high praise might with justice be accorded to
the work of Cope on the functional evolution of the various types of
limb-skeleton in Vertebrates, and on the evolution of the teeth as well
as to the work of other American palaeontologists, including Osborn
himself.

Osborn's law of "adaptive radiation," which links on to Darwin's law of
divergence,[553] constitutes a brilliant vindication of the functional
point of view. "According to this law each isolated region, if large and
sufficiently varied in its topography, soil, climate, and vegetation,
will give rise to a diversified mammalian fauna. From primitive central
types branches will spring off in all directions, with teeth and
prehensile organs modified to take advantage of every possible
opportunity of securing food, and in adaptation of the body, limbs and
feet to habitats of every kind, as shown in the diagram [on p. 363]. The
larger the region and the more diverse the conditions, the greater the
variety of mammals which will result.

"The most primitive mammals were probably small insectivorous or
omnivorous forms, therefore with simple, short-crowned teeth, of
slow-moving, ambulatory, terrestrial, or arboreal ha