LINNZZAN DEFINITION OF SPECIES. 89 
Those who defend the stability of species rather imagine 
that, with Cuvier, they are entitled to interpret facts in 
their own favour; whereas they partly remain uncon- 
sciously involved in hereditary prejudice, and partly 
contrive to be deliberately blind to all that evidently 
contradicts the immutability of species. 
Since Linnzus referred to the Creation, he attributed 
the individuals to a species, of which the pedigree 
ascended in direct line to the pair which proceeded 
from the hand of the Creator. Owing to the state of 
science in general, an examination of this pedigree was 
totally impossible in his time; and, indeed, with the 
strict reliance on sacred tradition, it was scarcely neces- 
sary. Cuvier, although a very unprejudiced and cool 
observer, nevertheless radically accepted the Linnzan 
definition of species. According to him, the species 
is the aggregate of individuals descending from one 
another and from common ancestors, and of those 
who resemble them as strongly as they resemble one 
another.” 
“In this definition,” says Haeckel, “to which the 
majority have ever since more or less closely achered, 
two things are obviously required of an individual as 
belonging to a species: in the first place, a certain 
degree of resemblance or approximate similarity of 
character; and secondly, a kindred connection by the 
bond of a common descent. In the numerous attempts 
of later authors to complete the definition, the chief 
stress is laid sometimes on the genealogical consangui- 
nity of all the individuals, sometimes on morphological 
uniformity in all essential characters. But it may be 
generally asserted that in the practical application of 
