STRUCTURE AND LIFE-HISTORY OF COPROMONAS SUBTILIS. 109 
this divides. Presumably new flagella subsequently grow 
from the daughter-nuclei, as from the basal granules of 
Copromonas. A similar condition appears to exist in 
Mastigina, according to a recent paper by Goldschmidt (22). 
In some Bodos the basal body is as large as the nucleus, 
and stains very strongly with nuclear stains. It divides in 
division of the monad. 
Unfortunately, although many interesting comparisons can 
be made, the problem of the homologies of these various 
structures must still be left unsolved. It can be settled by 
further research only. At present it is not possible to make 
any definite pronouncement on the subject. 
Conjugation. 
Much controversy has taken place on the subject of con- 
jugation in the Flagellata. Only a few years ago it was 
denied that any conjugation existed in the group. But now, 
owing largely to the labours of Prowazek, it can be definitely 
stated that conjugation occurs here as in all the other chief 
subdivisions of the Protozoa. 
Karly observers—Cienkowski, Stein, and others—described 
fusions between two monads in various species, interpreting 
them as processes of conjugation. In the years 1873 to 1875 
the remarkable observations of Dallinger and Drysdale (12) 
appeared, and gave rise to much dispute. Processes which, 
if they really exist, must be described as conjugation, were 
recorded in many monads, which have subsequently been 
referred to the genera Polytoma, Bodo, Monas, Cerco- 
monas, etc. Following conjugation, some remarkable 
methods of sporulation, including the formation of ultra- 
microscopic ‘‘ microspores,” were claimed to have been seen. 
Saville Kent (24) accepted the work of these two observers, 
but Biitschli (6) regarded it with great scepticism, admitting 
that conjugation takes place in the Phytomonadina only. A 
similar attitude was adopted by Klebs (28) in 1892, and by 
Blochmann (4) three years later. In the latest systematic 
