J 
as Infusoria flagellata. 259 
“The most striking peculiarity of this creature is its habit 
of swinging around on a pivot (j/*), which consists of an ovate 
or lancet-shaped appendage, of considerable dimensions, that 
projects from near the posterior end of the body, and in the 
line of the row of cilia. The pivot possesses perfect flexibility 
at its base, so that the sired can move over a considerable 
distance backward and forward without disturbing the point. 
Most of the time it keeps the flat side down when gyrating 
around its place of attachment; but now and then it turns 
upon its right edge, and performs its eccentric rotations about 
the appendage. This is the habit which, as I said before, has 
impressed some observers with its similarity to the Rotifera. 
In connexion with this, too, it happens that the creature pos- 
sesses a pair of jaw-like or, rather, pincer-like bodies (m!), 
which lie near the entrance to the mouth, and occasionally 
open and shut like a pair of forceps, ey as similar bodies 
known as the jaws of Rotifers do, whilst food is passing be- 
tween them. Excepting the passage between these jaws, there 
is not the least trace of an intestine, or of any definite cavity 
devoted to digestion. The food occupies the whole length and 
breadth of the body, under the same circumstances as are ob- 
servable in Paramecium, Pleuronema, Stentor, &c. 
“‘ The contractile vesicles are two (cv,cv) quite small globular 
bodies, one of which is situated just to the right of the jaws 
(m), and the other close to the base of the pivot (#2); and, 
although they contract very slowly (not oftener than once in 
four or five minutes), they evince every characteristic, in action 
and physiognomy, of true infusorian pulsating vesicles. The 
large colourless reproductive organ (z) singularly exemplifies 
in itself the one-sidedness of the animal, by its conformation to 
the shape of the body. One side of it is convex, and, like the 
rest of the organization, projects into the concavity of the 
larger shell, whilst the other face is flat and, as it were, 
moulded upon the plane shell. It forms a very conspicuous 
object just to the left of the jaws, and might easily be mistaken 
at first glance for a contractile vesicle, especially as the true 
representatives of that organ are so very inconspicuous both in 
regard to their size and actions. 
* Now in all the organization of this animal there is nothing 
which is not strictly infusorian in character. The jaw-like 
bodies (m1) are not confined to this alone; for there are quite a 
number of others which possess a similar apparatus at or near 
the mouth. Chilodon has a complete circle of straight rods 
around the mouth. As for the pivot (/i?), it is nothing but a 
kind of stem, such as exists on a larger scale in Stentor, or is 
more peculiarly specialized in the pedestals of Epistylis, Zootham- 
