126 HazEN: NEW SPECIES OF LOBOMONAS 
SEXUAL REPRODUCTION apparently has not been observed hith- 
erto in this genus. I considered it good fortune, therefore, to dis- 
cover three or four cases of conjugation taking place almost 
simultaneously in one hanging drop. The gametes have the 
general form and character of the vegetative cells, but are much 
smaller, provided with an excessively delicate cell wall, and the 
cilia are longer than the cell body. In the first case seen, one 
gamete was rather broad and pillow-shaped, with a distinctly 
visible cell wall, while the other was narrower and probably more 
nearly cylindrical, and furnished with a wall so delicate that it 
was detected only in its subsequent behavior. The two gametes 
became engaged by. their cilia, but not otherwise in contact, 
and remained in this position for at least a half hour, with slight 
dancing movement (FIG. 15); the cilia, most if not all of this 
time, were trailed backward along the sides of the narrower 
gamete. The first movement toward joining was in a sudden 
break of the anterior papilla of the broad gamete, whereby a 
broader papilla of colorless cytoplasm surged forward and pres- 
ently plastered itself on the beak of the unchanged gamete (FIG. 
16), the remainder of the protoplast of the broader gamete then 
distinctly withdrawing from the posterior part of its wall (FIc. 
17). Now for a period of about a half hour the remainder of 
the protoplast of the broader gamete was gradually oozing out 
of its wall and into the narrower gamete: even yet the narrower 
gamete hardly showed a wall, but it seemed evident that one 
must be present, since the posterior part of this gamete rigidly 
retained its original form (Fics. 19, 20). After this point more 
active ciliary movement carried the zygote beyond possibility 
of observation. 
A second case showed a similar figure of the narrow gamete 
remaining rigid for as long a time as it could be followed. In 
all probability this wall of the narrow gamete is finally thrown 
off separately, permitting the rounding up of the plasmatic mass 
to form a spherical zygospore. A third case showed the gametes 
more nearly equal, and it was clear that the walls of both were 
practically alike in character and not easily abandoned(FIG. 21 )y 
so that fusion was long delayed. 
There is in this species apparently little differentiation be- 
tween the gametes; indeed one might be inclined to regard the 
difference in size as merely accidental. Nevertheless from the 
behavior of the cilia, that is, both pairs for the most of the time 
stretching back alongside the narrower gamete, one may assume 
