152 ChlorophycedB 



Series III. Chroolepoidales. 



Family : Chroolepidacese. 

 Series IV. Siphonales (sensu Oltmanns). 

 B. Pleotrichales. 



Series I. (Edogoniales. 



Family : (Edogoniacese. 

 0. Atrichales. 



Series I. Conjugate. 



Families : Desmidiacese ; Zygnemacese. 



It will be noticed that the Heterokontse are missing from the above scheme, Chodat 

 having placed them [along with the Peridiniese, Bacillariese, and the Euglenacese] within 

 the Phseophycese ! 



The creation of the three new names Meiotrichales, Pleotrichales and Atrichales 

 seems scarcely necessary, as they are merely equivalent to the older and better names 

 of the Isokontse, Stephanokontse and Akontse. Moreover, they have the great disadvantage 

 that the termination ' -trichales ' (and also * -trichacese ') in the group-names of Algee has 

 so far been exclusively used in reference to hair-like branches and filaments, and not to cilia. 

 It is doubtful if there is any real justification for the inclusion of the ' Pleurococcacese,' 

 Ulotrichacese and Chsetophoracese within the one series of the ' Pleurococcales,' apart 

 from the extraordinary use of this group-name to include filamentous and branched Green 

 Algee. The Chsetophoracese are merely the branched forms of the Ulotrichacese, and the 

 evolutionary series of the latter through such forms as Geminella, Stichococcus, etc., is 

 almost perfect, the most probable origin of the lower types being from some of the 

 Tetrasporine Protococcales with thin cell-walls and simple parietal chloroplasts. Chodat 

 also includes the Ulvacese in his ' Pleurococcales,' without giving any reasons for such a 

 step, and he places Bulbochxte (surely by an accident) in the Coleochsetacese. 



[The foregoing classification has been very recently modified by Chodat ('13), the 

 principal alterations being in the 'Meiotrichales,' in which 'series I Protococcales' is 

 changed to ' series I Cystosporese ' and ' series II Pleurococcales ' is changed to ' series II 

 Parietales.'] 



V. WILLE ('09) recognizes neither the Heterokontse nor the Stephanokontse, and his 

 proposed new classification is in some ways a retrogression. He still maintains the 

 Conjugate as a group equivalent to the remainder of the Green Algse ('Chlorophycese'), 

 and the various members of the Heterokontse are scattered with little regard to their 

 affinities among the families of the Protococcales and the Chsetophorales. It is difficult to 

 see any reason for the inclusion of both Tribonema and Microspora in the Ulotrichaceae. 

 Following West ('04) and Oltmanns ('04), Aphanoch&te is regarded as the type of a separate 

 family. Wille's ' Pleurococcacese ' is a very mixed assemblage, including some members of 

 the Palmellacese and Heterokontse, and one lichen (Botrydina). Elakatothrix is also 

 included in the Pleurococcacese, although this genus is so closely related to Ankistrodesmus 

 as to be hardly separable from it. His Chsetophorales is enlarged in scope and somewhat 

 unwieldy, and is certainly not equivalent to the ' Confervales.' His system is briefly as 

 follows : 



Chlorophycex. 



Class Protococcales. 



Families : Volvocacese ; Tetrasporacese ; Botryococcaceae ; Pleurococcacese ; 

 Protococcacese ; Ophiocytiacese ; Hydrogastraceae ; Oocystacese ; Hydro- 

 dictyacese ; Ccelastraceae. 



