172 ^ CENTURY OF PROGRESS IN 7HE NATURAL SCIENCES 



related, even if only remotely, to both the Chrysophycophyta, especially the Ba- 

 eilariophyceae, and the Pyrrophycophyta (cf. Strain, 1951, p. 253). The evi- 

 dence derived from the structure of tlie flagella in these three groups (Petersen, 

 1918, 1929; Vlk, 1931, 1938; Deflandre, 1934; Longest, 1946; Koch, 1951; Man- 

 ton and Clarke, 1951a, 1951b) suggests that a closer relationship exists between 

 the Phaeophycophyta and Chrysophycophyta than between either of these two 

 groups and the Pyrrophycophyta. 



The following arrangement of the Phaeophycophyta is essentially that of 

 Papenfuss (1951a). 



Phylum PHAEOPHYCOPHYTA Papenfuss (1946, p. 218) 

 Syn.: Phaeophyta Wettstein (1901, p. 46) 

 Class Phaeophyceae De Bary (1881, p. 14) 



Syn.: Melanospermeae Harvey (1836, p. 157); Melanophyceae Rupreclit (1851, p. 

 206) ; Phycopheinophycees Marchand (1895, p. 15) 



Order ECTOCARPALES Setchell et Gardner (1922, p. 403) 



Family Ectocarpaceae (C. Agardli) Kiitzing orth. mut. Harvey (1849, 



p. 11) 



Syn.: Streblonemaceae Kylin (1947, p. 45), nomen nudum; Acineto- 

 sporaceae Bornet orth. mut. Hamel (1931: p. 8; cf. Kornmann, 1953) 

 Family Ralfsiaceae Hauck (1883, p. 318) 



Syn.: Lithodermataceae Hauck (1883, p. 318); Strangulariaceae 

 Stromfelt (1886, p. 49); Nemodermataceae Feldmann (1937, p. 121) 

 Order SPHACELARIALES Oltmanns (1922b, p. 83) 

 Syn.: Discosporangiales 0. C. Schmidt (1937a, p. 3) 



Family Sphacelariaceae J. Agardh orth. mut. Cohn (1872a, p. 17) 

 Family Stypocaulaceae Oltmanns (1922b, p. 95) 

 Family Cladostephaceae Oltmanns (1922b, p. 102) 

 Family Choristocarpaceae Kjellman (1S91, p. 190) 

 Syn.: Discosporangiaceae 0. C. Schmidt (1937a, p. 3) 

 Order CUTLERIALES Oltmanns (1922b, p. 109) 



Family Cutleriaceae (Thuret) Hauck (1883, p. 318) 

 Order TILOPTERIDALES Kylin (1917, p. 308) 



Family Tilopteridaceae (Thuret) Cohn orth. mut. De Toni (1891b, p. 182) 

 fFamily Masonophycaceae O. C. Schmidt (1937b, p. 5) 

 Order DICTYOTALES Kjellman (1893, p. 291) 



Family Dictyotaceae Lamouroux orth. mut. Dumortier (1829, p. 76) 

 Syn.: Zonariaceae (S. F. Gray) Nageli (1847, p. 179) 

 Order CHORDARIALES Setchell et Gardner (1925, p. 570) 



Family Myrionemataceae (Nageli) Foslie orth. mut. Skottsberg (1907, 



p. 49) 



Family Elachistaceae Kjellman (1890, p. 41) 



Family Corynophlaeaceae Oltmanns (1922b, p. 23) 



Syn.: Leathesiaceae Setchell et Gardner (1925, p. 507) 

 Family Chordariaceae (C. Agardh) Greville orth. mut. Harvey (1849, 



p. 11) 



Syn.: Mesogloeaceae Kiitzing (1843, p. 32); Myriogloiaceae Kuckuck 

 ex Setchell et Gardner (1925, p. 555) ; Heterochordariaceae Setchell et 

 Gardner (1925, p. 549) ; Aegiraceae Setchell et Gardner (1925, p. 543) ; 

 Myriocladiaceae Kuckuck (1929, p. 63) 



Family Spermatochnaceae Kjellman (1890, p. 32) 



Syn.: Stilophoraceae (Nageli) De Toni et Levi orth. mut. Kjellman 

 (1890, p. 34) 



Family Acrothrichaceae (Oltmanns) Kuckuck (1929, p. 66) 



Family Chordariopsidaceae Kylin (1940a, p. 53) 



Family Splachnidiaceae Mitchell et Whitting (1892, p. 9) 



