Dysmorphococcus variabilis, gen. et sp. nov. 
BY 
H. TAKEDA, D.I.C. 
With fifteen Figures in the Text. 
T HE Alga which is here described under the name of Dysmorphococcus 
variabilis was found in gatherings made during October, 1915, in 
a small stagnant pond in Richmond Park, Surrey. It occurred sparingly, 
associated with some species of Closterium , Cosmarium , Ch lamyd 0 mon as , 
Carteria , several species of Engle n a (e. g. E. oxyuris, Schmarda, E. spirogyra , 
Ehrb., &c.), Lepocinclis (e. g. forms of Z. ovum (Stein), Lemm., L . Steinii , 
Lemm., &c.), Phacus (e. g. Ph . caudata , Hiibn.,/Vz. longicauda (Ehrb.), Duj., 
and its var. torta, Lemm., Ph. parvida, Klebs, Ph. pusilla, Lemm., forms of 
Ph. pyrum (Ehrb.), Stein, Ph. tenuis , Swirenko, Ph. triqueter (Ehrb.), Duj., 
&c.), Trachelomonas (e. g. forms of Tr. hispida (Perty), Stein, Tr. rugulosa , 
Stein, Tr. Stokesiana , Palmer, forms of Tr. volvocina , Ehrb., &c.), and 
Vacuolaria virescens , Cienkowski. 
Externally the organism under consideration very much resembles the 
small subglobose form of Trachelomonas volvocina , Ehrb. It can, however, 
at once be distinguished from the latter, even under a low power of the micro- 
scope, by the fact that while it swims about, rotating on its own axis, and, 
so far as ascertained, always forwards, it presents a more or less angular 
appearance, due to its irregular shape. An examination under a high 
power reveals the fact that the organism does not belong to this genus, 
although there is at least one species (probably new) of Trachelomonas 
having a shell compressed in a somewhat similar way. 
The organism in question possesses a hard, brittle shell, similar in 
texture to that in the majority of species of Trachelomonas , brown to dark 
brown in colour, and extraordinarily irregular and variable in shape. The 
shell easily cracks and breaks up into irregular pieces when subjected to 
slight pressure, or when fairly strong glycerine is added to the water under 
the cover-slip. The shell is about 1 [x in thickness, and is ornamented with 
very minute and regularly arranged granules which resemble the dots in 
a half-tone print (Fig. 7,/). These granules are in some cases very faint, 
yet can always be detected, at any rate in all the specimens examined. It 
[Annals of Botany, Vol. XXX. No. CXVII. January, 1916.] 
