. 
182 TRANSACTIONS OF THE [FeB. 12, 
SECTION OF BIOLOGY. 
The following papers were read: 
“The Morphology and Significance of the variations of the 
Biceps flexor cubiti,” by Geo. S. Huntington. 
Our Conception of ‘‘Species” as Modified by the Doctrine 
of Evolution. 
By N. L. Britton. 
One of the most familiar axioms laid down in modern writings 
is to the effect that the word ‘ species” is most difficult to 
define. This difficulty is, indeed, cumulative, as the number of 
different living organisms known increases, each ‘“ new species” 
brought to light showing some peculiarity. of structure or form 
in which it differs from all others, but also indicating by some 
other characters its genetic relationship to its kin. Thus, as our 
knowledge of living ‘things increases, our notions of their rela- 
tionships undergo Mmodification, in groups of lower rank as well 
as in those of higher. It is clear that the naturalists of the early 
part of the century had far less difficulty with the “ species” 
question than we of to-day, and the disrepute which it has been 
sought by some narrow-minded writers to shroud the whole sci- 
ences of Systematic Botany and Zodlogy has been largely 
initiated by the inherent difficulty of the subject. Indeed, at 
the present day it is only the very broadest kind of training 
coupled with acute faculties for observation and intimate ac- 
quaintance with an enormous number of different organisms that 
equip a student asa really successful systematist. What wonder 
is it then that so few attempt these lines of research ? 
The difficulty surrounding the delimitation of species has for 
its origin, according to modern scientific thought, the past con- 
dition of organisms as well as their present. Believing, as we 
do, that the now-existing plants and animals are descended from 
preéxistent ancestors, more or less different, and recognizing 
the effects, though we are as yet unacquainted with the cause of 
the phenomena “which we designate as atavism and reversion, 
we understand, imperfectly, to be sure, but more and more 
accurately, how it is that organisms present so much variation 
within rather a limited field, for we realize that they are only 
showing some indications of their ancestral condition, It ismy 
opinon, based on a considerable amount of observation on liv- 
ing plants, that the atavistic tendency has not been given the 
