loo 



greater affinities witii the Archegoniatae, or less affinities with the 

 main grou[)s of algae, than the latter do among themselves. In 

 the arrangement of the classes, and more particularly of the 

 genera and families within the orders, it would be much more 

 convenient for most teachers if the author had proceeded from 

 lower to higher instead of in reverse order. 



It is among the green algae that the greatest advance has 

 been made recently and the chief value of this book is in the re- 

 classification of these groups, for the old class Chlorophyccae 

 cannot longer be maintained as a single group. Professor West's 

 scheme is admittedly not original. He has followed the main 

 lines marked out by Bohlin (1901) and Blackman and Tansley 

 (1902) ; but he has taken only the best features of their rather 

 brilliant and suggestive systems, and fallen back on the more 

 conservative lines suggested by his own wide experience in 

 various groups. The central idea in the recent systems is to go 

 back to different flagellate ancestors for each of the classes of 

 algae. The order Confervales (which might better be called 

 Tribonematales) proposed by Borzi in 1889, and enlarged by 

 Luther to the class Heterokontae, based upon a ciliated unicel- 

 lular form having yellows-green chromatophores and producing 

 oil rather than starch, on the whole, appears to be a very natural 

 group ; but we agree with Professor West that Vatichcria is too 

 divergent a form to be included here. The author is wise also 

 (and here he follows Bohlin) in retaining the Conjugatae and 

 Oedogoniales as orders under the Chlorophyccae. The ph\-- 

 logeny of these groups is indeed puzzling, and the proposition 

 of Blackman and Tansley to regard them respectively as classes 

 Akontae and Stephanokontae, coordinate with the Chlorophy- 

 ccae (Isokontae), furnishes an attractive and well-rounded scheme, 

 but we have no evidence that they have had a similar origin in 

 ciliated unicellular forms. On the contrary. West has argued 

 well for the derivation of the Conjugatae from other filamentous 

 forms. The orders Schizogoniales and Microsporales are here 

 separated from Ulvales and Chaetophorales, and Cladophorales 

 from Siphoneae. The creation of the ne\\- family Microtham- 

 niaceae appears to be superfluous, for my work has shown that 



