Some Aspects of the Algcz. 
39 
gametes are liberated and of the phenomena of fertilisation, 1 but 
the discussion of the homologies of the reproductive organs is not 
entirely satisfactory. Professor Oltmanns, of course, homologises 
all gametes and (most) zoospores. That, of course, is common 
ground, but we think his exposition would have gained in simplicity 
and clearness if he had laid stress on the swarmer as the direct 
representative of the vegetative individual of the primitive motile 
forms derived from the Flagellates. Whether it is or is not capable 
of conjugation in any particular case is of very little consequence 
from the broad phylogenetic standpoint. The view put forward by 
Professor Oltmanns that all zoospores are not necessarily homo¬ 
logous, some having probably developed independently, is, in our 
opinion, unlikely in the highest degree. The hypothesis of the 
development de novo of so specific a structure as the motile flagellated 
cell from a motionless algal cell, when there is the best general ground 
for the belief that the motionless cells in question had flagellated 
ancestors, seems to us to amount to the artificial manufacture of 
phylogenetic difficulties. The synzoospore of Vnuclieria is no 
doubt an organ of a peculiar composite nature (like the syngametes 
of certain Fungi), but it is no more an organ sui generis in the 
strict sense than (say) a Composite inflorescence is. Its existence 
is, in our view, rather an argument against supposing Vaucheria to 
represent an offshoot of the Siphoneae. 
A considerable section of the work is devoted to the algal cell; 
cell-wall, protoplasm, nuclei, centrosomes, karyoids, chromatophores 
and vacuoles being treated separately. Of these the cell-wall, and 
especially the chromatophores, on account of their great variety of 
form and structure, occupy the most space. The treatment of the 
nucleus strikes us as too slight. Fragmentary as our information 
on the cell-nuclei of the Algae still is, some more serious attempt 
should have been made to sum up the conclusions that may be 
drawn in regard to its structure, function and evolution. 
The impression left by Professor Oltmanns’ accounts of the 
cell-wall and chromatophores is of the extraordinary diversity of 
these structures among the Algae, due to the number of different 
experiments Nature has tried in these fields and to the variety of 
conditions, mechanical and illuminative, under which the Algae exist. 
The chromatophores, in respect of their relative constancy and 
1 We can confirm, from personal observation, Chmielevsky’s 
account of the degeneration of the chromatophore belonging to 
the male gamete in the zygote of a certain species of Spirogyra, 
an account as to which Professor Oltmanns seems to entertain 
pome doubt, 
