1895.] Search for the Unknown Factors of Evolution. 435 
strongest support in paleontology, and is the unconscious 
motive of dissent on the part of all paleontologists, so far as 
I know their opinions, independently working in all parts of 
the world, to the fortuitous Variation and Selection theory. 
Our paleontological series are unique in being phyletic 
series. They exhibit no evidences of fortuity in the main 
lines of evolution. New structures arise by infinitesimal be- 
ginnings at definite points. In their first stages they have no 
‘utilitarian’ or ‘survival’ value. They increase in size in suc- 
cessive generations until they reach a stage of usefulness. In 
many cases they first rise at points which have been in maxi- 
mum use, thus appearing to support the kinetogenesis theory. 
In extensive fossil series we also find evidence of anomalous or 
neutral variations, such as Bateson has brought together, but 
these are aside from the main lines of evolution. They pre- 
sent no evidence for the Neo-Darwinian principle of the 
accumulation of adaptive variations out of the fortuitous play 
around a mean of adaptive and inadaptive characters, but they 
present strong evidence of the Darwinian principle of the sur- 
vival of the fittest. The main trend of evolution is direct and 
definite throughout, according to certain unknown laws and 
not according to fortuity. This principle of progressive adapta- 
tion may be regarded as inductively established by careful 
studies of the evolution of the teeth and the skeleton. Its 
bearing upon Lamarck’s factor of the transmission of somato- 
genic variation was pointed out by myself in 1889 ; it does not 
positively demonstrate Lamarck’s factor because it leaves open 
the possible working of some other factor at present unknown, 
and Lamarck’s factor is also inadequate; but it positively sets 
aside Darwin’s factor as universal in the origin of adaptations 
and as a consequence ‘ the all-sufficiency of Natural Selection.’ 
If Lamarck’s factor is disproved, in other ways, it leaves us in 
vacuo so far as a working hypothesis is concerned. 
The conclusions which Hyatt, Dall, Williams, Buckman, 
Lang, and Wiirtemberger have reached among invertebrates 
are independently paralleled by those of Cope, Ryder, Baur, 
Scott,” the writer, and many other morphologists. The same 
n W, B. Scott: On Some of the Factors in the Evolution of the Mammalia. 
Journ. of Morphology, vol. V, 1891, p. 378. 
