Monthly Microscopical"] 
Journal, May 1, 1869. J 
Boyal Microscojn'cal Society . 
^ 289 
III. — On some New Infusoria from the Victoria Docks. 
By Wm. S. Kent, F.E.M.S. 
{Head he/ore the Royal Microscopical Society, April 14, 1869.) 
Among the variety of forms of Infusorial life inhabiting the brackish 
waters of the Victoria Docks, two or three have come under my 
notice which seem to differ considerably from any species hitherto 
described. 
My attention was directed to the species I shall first refer to, 
by Mr. Walter Eeeves, Fellow of the Society, and to whom is due 
the credit of first discovering it. It belongs to the genus Cotlmrniay 
but is readily distinguished from all other species belonging to that 
genus, by its possessing a well-developed operculum. This oper- 
culum is attached to the body of the animal immediately beneath 
the peristome, and being somewhat smaller than the aperture of 
the lorica, or investing-sheath, is drawn down into it on the animal 
retracting. A slight flexure of the disc now results, and the 
operculum then entirely conceals beneath it all the softer parts of 
the body, which are thus efficiently protected from fear of intrusion 
from without. 
A like result, but through entirely different means, is arrived at 
in Vaginicola valvata of Wright, in which species a valvular trap- 
door-like apparatus is developed from, and attached by a hinge- 
joint to, the interior of the lorica, or investing-sheath ; but this, 
from its mode and position of attachment, never makes its appear- 
ance on the outside of it. 
The average length of the lorica in the species here introduced 
is 1-400", and this, in common with the operculum and the 
proximal attachment of the pedicle, is composed of a substance 
resembhng chitine, which, in the adult condition, is of a dark chest- 
nut hue, the pedicle alone remaining perfectly transparent. At an 
earlier stage of growth the chitinous matter is of a pale amber 
EXPLANATION OF PLATE XII. 
Fig. 1. — Cothurma operculigera— Specimens attached by their pedicles to the 
lorica of a larger species of the same genus, x 130. 
„ 2, 8, 4. — Individuals of tlie same species still further enlarged, showing the 
position of the operculum when the animal is fully expanded, and in 
different stages of retraction. 
„ 5. — Euplotes paradoxa. — At a are represented the ramose setsG, while the 
arrows at h indicate the direction of the current produced by the 
vibration of the flagelliform cilia placed in the vicinity of the oral 
region, x 250. 
„ 6. — Acineta socialis, X 160. 
„ 7. — A single individual of the same, x 660. 
