1884.] Notices of some new Parasitic Infusoria. 1083 
cilia, or, when momentarily seen, they appear as a single fila- 
ment. 
Extending along the entire length of one lateral border is a 
narrow, rapidly undulating membrane, very readily mistaken for a 
spirally twisting flagellum. Its free edge seems to be thickened, 
and its line of insertion on the body has the appearance of a dis- 
tinct filament or ridge. That this usually conspicuous line is not 
a flagellum is proved by its invariable adherence to the surface. 
It has never been observed to lift itself or to exhibit independent 
movement; it always follows the contortions of the body and 
always keeps the same relative position in reference to the margin 
of the undulating membrane. It is, however, very liable to be 
confounded with a long, thread-like filament which springs from 
the terminal margin of the membrane. This appendage, unique 
in its position, seems to have no individual freedom of motion, 
but follows and completes the undulations of the tissue to which 
it is attached, as the lash follows the brandished whip-stock. 
That it has no other connection with the body proper I am con- 
vinced, although it is as fine and as difficult to satisfactorily ex- 
amine as are the three anteriorly inserted flagella. 
The parenchyma is usually more or less vacuolar. It becomes 
conspicuously so when surrounded by water, the vesicles varying 
in size and often changing their position rapidly. A true pul- 
sating vacuole is absent. The nucleus is also obscure. Occa- 
sionally a small refringent disc, usually structureless, rarely gran- 
ular, is noticeable near the center of one lateral border, and may 
be the endoplast. 
Longitudinally traversing the zodid from the apex to the pos- 
terior extremity, where it conspicuously projects, is a flexible, 
somewhat curved and rod-like body, enlarged at its origin, thence 
of a constant width to the distal end where it becomes suddenly 
acuminate. The point of exit from the sarcode is well marked, 
the cuticular surface occasionally appearing to surround it for a 
short distance like a sheath, When the animal is immersed in 
pure water it becomes shortened and permanently fusiform, and 
is rod then protrudes an increased length which small pror- 
Plasmic drops often cover. What the function and constitution 
of this motionless and refringent structure may be, it is difficult 
to conjecture. 
No oral aperture is visible. Very rarely a few small dark- 
