150 Chlorophyceae 



Group 2. Tetrasporineae. 



Families : Tetrasporaceae ; Glreocystaceae ; Selenastracese ; Phytheliaceae ; 



Pleurococcacese. 

 Group 3. Chlorococcineae. 



Families : Chlorococcacese ; Endosphseraceae ; Hydrodictyaceae. 



Series 2. Siphonales. 

 Group 1. Siphoneae. 



Families : Protosiphonacese ; Bryopsidaceae ; Derbesiacese ; Caulerpacese ; 



Codiaceae ; Verticillatae. 

 Group 2. Siphonocladeae. 



Families : Valoniaceae ; Gomontiacese ; Cladophoraceae ; Sphaeropleaceae. 

 Series 3. Ul vales. 



Family : Ulvaceae. 

 Series 4. Ulotrichales. 



Families : Ulotrichacese ; Prasiolaceae ; Microsporaceae ; Cylindrocap- 

 sacese ; Chaetophoraceae ; Chsetosiphonaceae ; Coleochaetaceaa ; Chroo- 

 lepidaceae. 



Class II. Stephanokontse. 



Family : CEdogoniaceae. 



Class III. Conjugate (Akontse). 

 Series 1. Desmidioidese. 



Families : Archidesmidiacese ; Eudesmidiaceaa. 

 Series 2. Zygnernoideae. 



Families : Spirogyracese ; Zygnemacese ; Mougeotiacese. 



Class IV. Heterokontse. 



Series 1. Chloromoiiadales. 



Families : Chloramoebaceae ; V r acuolariaceD3 ; Chlorosaccacese. 

 Series 2. Confervales. 



Families : Chlorotheciaceae ; Confervacese ; Botrydiaceae. 

 Series 3. Vaucheriales. 



Families : Vaueheriaceae ; Phyllosiphonaceae. 



II. In the Treatise on the British Freshwater Algae (G. S. WEST, '04) the classifica- 

 tion put forward was not essentially different from that suggested by Bohlin, except that 

 the genus Prasiola was placed in a separate group, the Schizogoniales. It would have 

 been better, however, if the Heterokontae had not been given such undue prominence, and 

 the Conjugatae removed from the middle of those Algae which are now regarded as 

 constituting the Isokontae. The detailed treatment of the Conjugatae was entirely different 

 from that followed by Blackman & Tansley, and the Vaueheriaceae were retained in the 

 Siphoneae. Bohlin was followed in regarding the genus Microspora as the sole representa- 

 tive of the group ' Microsporales.' 



III. OLTMANNS ('04) put forward a classification of Green Alga? in many ways 

 peculiar. His inclusion of the diatoms within the Akontse is not only extraordinary, but 

 constitutes an extension of the group ' Akontae ' which can hardly be countenanced and is 

 most decidedly confusing. Similarly, his division of the Conjugatse into the Mesotaeniaceae, 

 Zygnemaceee and Desmidiaceae, with the inclusion of Genicularia and Gonatozygon in the 

 Zygnemaceee, is not altogether in accordance with the present-day knowledge of this group. 



