35 i 
The Chicago University Text-Book. 
high standard of the rest of the section, but it leaves the impression 
that it is of little use to deal with so vast a subject in so short a 
space. 
The following passages in Part I appear to call for comment 
and criticism. 
On p. 16 it is said that “ The origin of gametes is the origin of 
sex, and isogamy is the simplest form of sexuality.” This un¬ 
qualified identification of the sexual process with the process of 
conjugation, without regard to the binary differentiation insepar¬ 
ably connected with the idea of sex in ordinary language and 
thought, may no doubt be defended, but it is at least necessary to 
point out the existence of the decreased connotation of the term 
as thus used. Otherwise confusion is inevitably created in the mind 
of the student. The result of reading part of the connotation of 
sex, as this word is understood in common language, into the 
process of isogamy, has left its mark on the history of the subject. 
It is unnecessary to insist on the danger of using common words 
with altered connotations in technical senses. 
In describing Pandorina (p. 17) the opportunity is missed of 
illustrating the origin of sex in the common sense, i.e., the binary 
differentiation of gametes. The life-history of Pandorina as described 
by Pringsheim is of fundamental importance precisely because it 
illustrates this phenomenon. The evolution of a soma in Pleodorina 
and its increase in size and importance in Volvox is not brought 
out, all reference to the former genus being omitted. The evolu¬ 
tion of the Volvocine series is one of the most instructive of 
all evolutionary stories, since it illustrates far better than any 
other the most fundamental differentiations in the organic world. 
The use of the word “ irregular ” as applied to chloroplasts of 
Desmids (p. 37) tends to convey a misleading impression. 
In dealing with Chara it is said, on p. 42, that “The axillary 
position of the main branch suggested that the smaller subtending 
branches are leaves.” This statement appears to require elabora¬ 
tion to make its significance clear. 
It seems a mistake to base the discussion of alternation of 
generations in the algae (pp. 31, 51, 60) entirely on the “chromo¬ 
some test.” Such a limitation must give the student a rigid and 
one-sided idea of a difficult and complex subject. 
The dominance, in America, of the pure antithetic theory of 
alternation as elaborated by Bower is reflected in the accounts of 
Antlioceros and of the Lycopodiales. These accounts, with the 
