F. Cavers. 
118 
colony is invested in mucilage through which the flagella protrude, 
in Synura (Fig. 6, 5) there is no mucilaginous covering and 
each cell of the colony has a firm periplast beset with spines or 
warty outgrowths—in 5. Klebsiana each cell bears two flinty 
spicules, as in Chrysosphcerclla. Pascher (110) has observed that 
in Synura uvella the contents of a cell may escape as an amoeba 
instead of a flagellate swarmer, and that the latter may also 
become amoeboid after liberation, and that from both flagellate 
and amoeboid forms palmella-states may arise by division in a 
mucilaginous motionless condition (Conrad, 26). 
The Ochromonadales, though a smaller order than the Chro- 
mulinales and Isochrysidales, shows parallel developments of the 
same kind. Here again we begin with a unicellular and potentially 
amoeboid type, Ochromonas (Fig. 6, 7-10), which, except in having 
two unequal flagella, closely resembles Chrysamoeba among the 
Chromulinales; most of the species are free-swimming, but O. 
tenera becomes fixed by its hinder end; the thin periplast is 
capable of secreting mucilage, and in O.socia division occurs in the 
motile phase and gives rise to small, generally four-celled, motile 
coenobia; usually, division occurs in a resting state, and in O. 
botrys a large mass of cells enveloped in mucilage may be formed 
in this way. In Cycloncxis (Fig. 6, 7 7, 12), the individual cells are 
like those of Ochromonas, but they remain in lateral contact in 
such a manner as to form a radiating ring-like coenobium, con¬ 
sisting usually of 16 cells. In Urogleua a curious type of coenobium 
is formed as the result of repeated division of the stalked cells and 
the formation of a spherical mucilage mass in which the cells lie 
near the periphery while the branching stalks radiate from the 
centre. In Dinobryon (Fig. 6, 13-16) the cell is spindle-shaped and 
is invested loosely by a vase-like shell widely open above; when 
division occurs, the daughter cells may either escape or (in most 
species) become attached to the mouth of the shell and produce a 
shell of their own ; by repetition of this process, a branching colony 
is built up; the shell in some cases gives cellulose reactions. The 
genus Dinobryon has been monographed by Brunnthaler (16) and 
by Lemmermann (79). 
VII,— The Cryptomonads and their Relationships. 
I T would appear that the three orders of Chrysomonadineae 
dealt with thus far (Chromulinales, Isochrysidales, Ochromo¬ 
nadales) have not given rise to anything higher than a Flagellate, 
though they show various attempts at the formation of colonies 
—in all three orders we find gradual elaboration of motile 
“ Volvocine” coenobia, and also the working out of a palmelloid or 
“ Tetrasporine ” tendency towards the formation and dominance 
of a non-motile multicellular vegetative condition. It may be 
noted that “ Volvocine ” coenobia occur also among the Proto- 
mastigineae ( Protospongia, Sphceroeca, etc.), in addition to the 
dendroid colonies of th e. Dinobryon type ( Codonocladium, Salpingceca, 
etc.) derived from solitary “ choanflagellate ” forms (i.e., forms 
with outstanding collar-bearing perisarc). Whether the remark¬ 
able resemblances between the “ mastigamoeboid,” the “ Volvo- 
