English Soils ; an Important Factor in Soil Biology . 49 
habitat. In this country no record of the species has ever been made, hence 
its appearance from no less than forty of the soil-samples under investiga- 
tion in the present work is all the more remarkable. 
Another interesting record is the finding of Chlorochytrium paradoxum 
in three of the soils. In the Himley (47) and Tisbury, A (49) samples the 
alga was present in considerable quantity, while in the Sutton Coldfield (48) 
sample a few isolated specimens only were observed ; the cells were 
embedded in a stratum formed of blue-green algae, but even this association 
is a great change from the endophytic habit that has previously been 
described for the species. 
Ankistrodesmus falcatus has hitherto been regarded as a purely aquatic- 
species, but relatively large colonies of very characteristic form (Text-fig. 1) 
Text-fig. 2 . Ankistrodesmus jalcatus, (Corda) Ralfs, forma terrestris. a., vegetative cells; 
b. and c ., stages in formation of autospores ; d., small colony of eight autospores ; e ., large colony 
showing characteristic arrangement of cells. Figs. a.-c. x 1435, Figs. d. and e. x 825. 
appeared in the cultures of the YVarley soil, and that after desiccation for 
more than five weeks. Hence it appears that this species possesses powers 
of resisting desiccation that seem almost incredible in an alga of such a size 
and form. It is probable that in the majority of cases Ankistrodesmus 
falcatus would be unable to withstand desiccation in this manner ; hence, in 
order to emphasize the unusual habitat and extraordinary powers of resis- 
tance of the alga in these cultures, it seems advisable to regard it as a special 
form of the species under the name A. falcatus, forma terrestris. 
The described species of Gongrosira also are aquatic in habit ; the 
form that has appeared from three widely separated soil-samples, while 
obviously belonging to this genus, differs from those already described in 
E 
