94 T. C. Hilgard—Infusorial Circuit of Generations. 
copulation, seeing that in the first place they neither develop 
=a eggs; nor, in the second place, do they even extrude | 
yolks; but their onward development is by encystment. 
Within a few minutes such a full-grown “oyster-grub” is — 
seen contracting its big flap, so as to present the shape ofa | 
at with a warped rim and hemispherical crown, the latter | 
lar is exuded. The speck or “eye” itself now becomes dusky 
and granular. It increases. It bisects “Gregarina-” fashion. — 
ach pear-shaped segment again acquires a clear speck oF — 
* eye.” 
They elongate, being connected by the blunt ends — 
each one tapering toa very soft apex; and these very large — 
germs or pseudo-Gregarinas at last become liberated, probably 
as “ Paramecium Aurelia,” which now appears full-grown on the — 
scene. | 
It is about the length of the Oxytricha, about three times — 
the length of the revolving wool-fringed grubs of the Oxy _ 
tricha, and by all means more complexly organized than either. 
It has the shape of the (shoemaker’s) /ast for a very elegant — 
ladies’ shoe. From one side it therefore gives the figure as of 8 | 
foot-print (without the toes); but viewed on edge has a poin 
rear end, and in this profile it “takes the name” of Parame 
cium caudatum! The ankle of that “last,” however, is beveled — 
away leaving the instep a ridge. Its oral aperture, not clearly — 
distinguishable, is in the middle, slanting almost longitudinally — 
for about one quarter of the length of the body. It seems 
circular a 
pulsatory vesicle, wherewith it — itself, and around which — 
= it is often seen spinning li os eB 
rm or bulbous vessels radiating around the pulsatory vesicle; | 
— as the vesicle expands, and vice versd, as is well-knowD; 
an av we 
body is turgid with rather small germinal yolks. These att | 
mals I have never seen bisecting either lengthwiset+ or across; 7 
nor copulating sexually. The latter, however, seems to 
(tween else, sewn bell apr) qn preserve ron ezncaton. 
betwe ips, somewh: 7 iccation. 
t Barasbergs Rguiaay Mowueds, show it in that process (if not a mistake). 
© The Aacz 
