STRUCTURE AND LIFE-HISTORY OF COPROMONAS SUBTILIS. 107 
(1) Flagella arising directly from the nucleus, as in 
Mastigameba, ete. 
(2) Flagella united to the nucleus by means of an inter- 
mediate link, the “zygoplast”—e.g. species of Monas, 
Chlamydomonadina, etc. 
(3) Flagella arising from a basal granule, independent of 
the nucleus, a condition seen in Copromonas. 
And to complete the list I will add: 
(4) Flagella arising from a special nucleus—the kineto- 
nucleus—as in the trypanosomes. 
An intermediate condition between (2) and (4) may be seen 
in Hemoproteus noctue, where kinetonucleus and 
trophonucleus remain united by an achromatic thread. 
Many varieties of (2) are to be seen. In Chlamydomonas, 
for example, the flagella are attached to a basal granule 
from which a strand—the rhizoplast—runs to the nucleus, 
on the membrane of which it ends in a knot-like enlargement. 
The first arrangement occurs also in the swarm-cells of 
Mycetozoa (Plenge [32]). It was first described in Mastig- 
amoeba aspera by F. EH. Schultze (46) in 1875, and has 
since been observed in allied forms by various writers 
(cf. Goldschmidt [22]). It may be compared with the attach- 
ment of the axopodial rays to the nucleus in Heliozoa—e.¢. 
in Camptonema (Schaudinn [41]), also with the axial rod 
and nucleus of T'richomastix (Prowazek [89]). Plenge 
has suggested that the flagellum in soft-bodied organisms 
hke Mastigamceba is attached to the nucleus because it 
happens to be a relatively fixed point. 
The homology of the basal granule still remains obscure. 
It has been thought to be homologous with the basal granule 
(end knob) of the tail filament of a spermatozoon. And the 
end knob has been shown from the work of Moore, Meves, 
Paulmier, Hermann, Lenhossék, Benda, Korff, and many 
others to be the centrosome.! The axial filament is an 
outgrowth of it. 
‘ It is beyond the scope of the present paper to enter in detail into the 
enormous literature on this aspect of the centrosome. The reader who seeks 
further information on the subject will find an excellent account in Maier (80), 
and also much that is of importance in Wilson (58). 
