Reviews. 
i 46 
Honnospora, Glceotila and Radiofilum to Ulotrichacese, and his 
placing of many of these unicellular genera, we are quite prepared 
to accept. A full discussion of the author’s arrangement of the Proto- 
coccales would occupy too much space, but we cannot help expressing 
the conviction that they are more naturally divided into three series 
according to the three main tendencies of evolution seen in the 
group, tendencies whose reality Mr. West fully accepts in his 
Introduction. 
The Diatoms are given a class to themselves and the Myxo- 
phyceae (Cyanophyceae) another. Mr. West is surprised that the 
earlier name, Myxophyceas, has never been adopted in text-books. 
The reason no doubt may be found in the fact that it is much more 
convenient to have a “pigment name” uniform with the others. The 
law of priority is troublesome enough to the average botanist when 
applied to genera and species, where we suppose it is really neces¬ 
sary,—witness the disappearance of Conferva before Tribonema in 
the present work,—but to expect us to bow to it in the case of larger 
groups is to strain our endurance too far. We must adopt the 
group names that are most convenient or most in accord with the 
present state of knowledge. Finality of group-nomenclature can 
only be obtained by a gradually reached consensus of expert 
opinion; it cannot be forced upon us by the operation of an arbitrary 
law. 
We think it a mistake to include Glaucocystis in “ Myxophy- 
ceae”; the cytological type is so different that, its pigment 
notwithstanding, this genus should not be associated with the 
entirely isolated typical blue-green algae. There is no evidence of 
phylogenetic connexion. 
One curious feature of the present book which is rather in 
accord with the non-evolutionary treatment of some of the morpho¬ 
logical topics considered in the Introduction, is the old-fashioned 
plan of arranging the systematic part so that we begin with the 
highest forms and end with the lowest. It is difficult to see what 
advantage is gained, while the disadvantage of departing from the 
evolutionary sequence is clear. 
In spite of the apparent weakness in some points, there is no doubt 
that Mr. West has conferred a very considerable boon upon British 
algologists in producing this work. The careful description, the 
large amount of first-hand information, the abundant original 
illustration of British species from named localities, combine to 
render the systematic treatment a work of very high value. 
A.G.T. 
