76 . C. CLIFFORD DOBELL. 
INTRODUCTION. 
I believe there is no group of Protozoa which has 
yielded more interesting results from its investigation than 
that of the Flagellata. Even since the wonderful work of 
Dallinger and Drysdale was published, the flagellates have 
been invested with a fascinating uncertainty regarding their 
reproductive capacities. And, although this work has never 
been confirmed, the recent discoveries of Schaudinn and 
Prowazek have revealed the existence of life-histories which 
are in no way less remarkable than those described by the 
English investigators. Yet in spite of all this the flagellates 
—with the exception of the trypanosomes—are much 
neglected by protozoologists. 
In so far as it indicated the sexuality of the group, the 
work of Dallinger and Drysdale has received confirmation. 
But the remarkable multiple fission and sporulation—includ- 
ing the formation of ultra-microscopic spores—which they 
saw have been seen by no one since. And hence, although 
we may indeed say that, as the result of recent work, ‘the 
pronounced scepticism of Klebs, Senn, and others with 
regard to the occurrence of a sexual process in this class 
is now completely refuted,” itis by no means legitimate 
to conclude that ‘the views of Kent and of Dallinger and 
Drysdale, are at length vindicated.” ! One form of “ repro- 
ductive granule” described by Dallinger and Drysdale 
appears to be in reality a starch grain! And Stein’s “endo- 
genous reproduction,’ from the nucleus in euglenoids turns 
out to be due to the presence of a parasite. There is still 
room for much research on the monads. With the possible 
exception of ‘‘Monas dallingeri’’ (Sav. Kent), no uni- 
flagellate monad has had its life-cycle worked out with 
any degree of completeness up to the present day. . : 
Having found a monad of this kind which can always be 
easily obtained, and is very well suited for microscopic 
1 « Zool. Rec. Protozoa,’ 1904. 
