J 4 2 
Reviews. 
introduction to a systematic work. Meanwhile it is important that 
students should not be given the impression that the phenomena 
of sex-differentiation and alternation of generations must be “ read 
into ” the life histories of primitive forms which are in fact innocent 
of such complications. 
The section on “ Polymorphism ” contains a very moderate and 
just, though brief, treatment of this very controversial topic. 
Nevertheless the statement that “all those Algae which exhibit an 
alternation of generations are polymorphic” again seems very mis¬ 
leading. Surely alternation of generations is quite a distinct pheno¬ 
menon from polymorphism, as usually understood, which presumably 
refers to the production of different alternative vegetative forms by 
one species. The facultative production of different kinds of 
reproductive cell by the same plant, which Klebs and others have 
established in many algae, and which may have given rise to homo¬ 
logous alternation in a form like Dictyota, might no doubt logically be 
referred to as “ polymorphism of reproductive cells.” But the 
succession of definite phases in a life-history cannot be included 
under the concept without a confusion of thought. 
The section on Phylogeny and Classification follows in its main 
ideas, so far as the Green Algae are concerned, the views put forward 
by Bohlin and by Blackman and made the basis of the “ Revision 
of the Classification of the Green Algae ” published in this journal 
in 1902. Various alterations based on the author’s own experience 
have been introduced. 
Mr. West, like Professor Oltmanns, accepts Luther’s Class 
Heterokontae, regarding it as a “very natural” group. We may 
look upon this series as now well on its way towards general 
acceptance among algologists. Mr. West also agrees with Professor 
Oltmanns in refusing to admit the affinity of the “ Vaucheriales” 
with the Heterokontan forms. The arguments for and against this 
position have been discussed in the recent review of Professor 
Oltmanns’ book in this journal. 
The rest of the green forms are still grouped under the old 
name Chlorophyceae, since Mr. West refuses to accept the thorough 
going breaking-up of this heterogeneous class and the establishment 
of different series based on the characters of the motile cell, 
proposed by Bohlin and adopted and carried further in the 
“Revision.” “This arrangement,” says Mr. West, “is based upon 
the assumption that the CEdogoniales and the Conjugatae are 
phylogenetically independent of ‘Isokontae’ and that all three 
groups have arisen from the Flagellata. Be it remembered, 
