The Classification of the Algae.. 95 
that the cytological details of redaction, etc., in oogenesis, could 
have been included. It is, we think, a mistake to divorce such 
important details from the special descriptions of the groups they 
refer to, however necessary it may be to consider them again in the 
course of general discussions. 
The Bangiales are treated as a separate group distinct from 
the Rhodophyceae, which name is taken as synonymous with 
Florideas. The great feature of the treatment of the Red Sea¬ 
weeds is a section of no less than 110 pages devoted to a 
description of their vegetative structure under two great heads— 
the “ Springhrunnen-typus 1’ and the “ Zentralfaden-typus.” This 
detailed and yet generalised treatment enables one to obtain an 
“Uebersicht” of the structure of these forms in a way that has 
never been possible heretofore. 
The reproductive processes of the Red Seaweeds, finally, 
occupy the concluding section of the work. Here Professor 
Oltmanns is dealing with a subject, to which his own work has 
contributed by far the most important advance of the last fifteen 
years. We need only note that in his arrangement of the families 
based on the structure of the sporophyte he follows Schmitz and 
Hauptfleisch in the main, departing from Schmitz’s grouping 
only in comparatively minor points. 
One of the principal risks to which an author is exposed in 
undertaking a full treatment of a group containing a very great 
number of varied forms is the danger of becoming lost in details. 
We do not for a moment suggest that Professor Oltmanns has 
actually fallen into this danger, but we do rather miss, particularly 
in some parts of his book, that broad evolutionary treatment, which 
we think might have illuminated and given more unity to this solid 
and well-informed work. The principles governing the evolution of 
plants are not always easy to disentangle, but in the case of the 
Algae, particularly the lower green forms, which are not, like the 
higher plants, burdened with a legacy of complex structure, there 
is rather an exceptional opportunity of obtaining a clear view 
of at least the proximate factors of evolution. It may be urged 
that this is scarcely a fair criticism to make on the “ special part ” 
of a work of which the “ general part ” is still unpublished, but the 
broad treatment referred to is wanted in actual connexion with the 
details to give them life and unity. It is perhaps hypercritical, 
however, to receive so solid, useful and attractive a work in such 
a spirit. We look forward to the author’s “ Allgemeiner Theil” with 
great interest. A.G.T. 
O 
