Flagellata and Primitive Alga. 
I 2 I 
chrysis, but in C. ovata starch is produced ; longitudinal division 
may occur in either the motile or the encysted condition, and the 
cyst membrane gives the reactions of the cellulose. Chroomonas 
and Cyanomonas resemble Cryptonioncis, but the chromatophores 
are blue-green, while Rhodomonas is allied to these forms but has a 
red chromatophore. Chilonionas (big. 7, 8) also resembles Crypto- 
jnonas in structure, but is saprophytic, though it produces starch ; 
Botryowonas (Schmidle, 131) is another saprophytic starch-pro¬ 
ducing form, in which the cells become aggregated to build up a 
branched gelatinous colony, and the periplast gives cellulose 
reactions. Cythomonas (Ulehla, 143) and Oxyrrhis (Senn, 136), 
though placed by Senn in the Protomastigineae, are apparently 
related closely to Cryptomonas through Chilonionas, and may be 
regarded as colourless forms derived from a Cryptomonas-Uke type; 
in Cyathomonas (Fig. 7, 9) nutrition is mainly saprophytic, but solid 
food can also be ingested at the anterior end of the body, while in 
Oxyrrhis nutrition is mainly holozoic and this genus differs from 
its allies in undergoing transverse division. 
The Cryptomonads have probably arisen from simple Chryso- 
monads, with two flagella either of unequal length or with different 
orientation (one directed forwards and the other backwards in 
swimming). Such a form as Ochronionas, for instance, may well 
have given rise to the Chloromonadineae on one hand and to the 
Cryptomonads on the other, for these two groups show somewhat 
striking parallelisms, such as the organisation of the vacuole 
system into small actively contractile vacuoles which open into a 
large anterior non contractile vacuole or into a groove or canal. 
The Chloromonads have probably given rise on one hand to the 
highly differentiated Euglenineffi which have no Algal affinities, and 
on the other to the Algal group “ Confervales ” (Heterokontae). 
Similarly the simpler Cryptomonads—e.g., Cryptochrysis and 
Protochrysis- —appear to have given rise on one hand to highly 
organised Flagellates like Cryptomonas , Chilonionas , Cyathomonas , 
and Oxyrrhis —corresponding to the Euglenineae in the green 
series—and on the other to the Phaeocapsaceae, which form the 
starting-point of the Brown Algae. 
The Phaeocapsaceae, corresponding roughly with the 
Tetrasporaceas and Palmellaceae in the green series, are apparently 
a somewhat heterogenous group, marked by the dominance of the 
non-motile phase. One of the simplest genera is Phczocystis 
(Fig. 7, 13-15) in which the cells have from one to four plate-like 
chromatophores and are aggregated to form a rounded gelatinous 
colony, the motionless cells being rounded, while the motile cells 
(“ zoogonidia ”) are biflagellate and have the same structure as 
Wysotzkia (Lagerheim, 73; Ostenfeld, 96; Scherffel, 122). In a 
similar form described by Reinisch (120) as Phceococcns marinus 
(Fig. 7, 10-12) but regarded by Pascher (104) as the type of a new 
genus, Phceoplax, the motile cells correspond closely to Cryptochrysis. 
Phceococcns Clementi is a gelatinous form adapted to subaerial life, 
the cells having firm envelopes, and the motile cells show typical 
Cryptomonad structure ; whether P. paludosa described by West 
(146) belongs to this genus, or indeed to the Phaeocapsaceae, is 
somewhat doubtful, since in his figures the motile cells resemble 
those of the Isochrysidal Chrysomonads and not the Cryptomonads. 
