290 ^ 
Transactions of the 
[Monthly MicroscopiL-al 
Journal, May 1, 1869. 
colour, readily permitting the contour of tlie contained animal to 
be defined through it, which is not possible after the darker adult 
hue has been assumed. As might be anticipated, however, every 
gradation of shade may be met with between the two extremes. 
Throughout February, and so far through March, this infu- 
sorium has been taken in considerable abundance in both the 
Victoria and the Commercial Docks, attached either to Cordy- 
lophora, various minute algae, or other organic substances. In 
more than one instance, I have observed small colonies which have 
selected the lorica of a larger species as their fulcrum for support, 
and from one of these, the accompanying illustration (Plate XII., 
Fig. 1) was taken. 
Hitherto, I have not met with, nor heard of a single instance 
in which two individuals have been found occupying the same 
lorica, and hence it may fairly be deduced, that propagation by 
longitudinal fission, in this species, rarely, if ever, takes place. 
While retaining the generic name of Cothurnia, I propose, in 
consequence of the peculiar apparatus above described, to distin- 
guish this form from other species by the specific name of oper- 
culigera, and its characteristics may be technically expressed as 
follows : — 
Lorica of a deep chestnut colour, somewhat gibbous, average 
length 1-400". Body hyaline, bearing beneath the peristome a 
circular, chitinous operculum, of the same hue and consistence as 
the lorica. Pedicle transparent, varying from the same to twice 
the length of the lorica. Inhabiting brackish water. 
Many microscopists would probably consider the characters 
afforded by this species of sufficient import to justify its being 
placed in a distinct genus ; but in that case, it would be equally 
desirable that Vaginicola valvata should undergo the same treat- 
ment ; and generic discrimination might certainly be based with far 
greater justice on the valvular apparatus of that species, and the 
opercular appendage appertaining to the one here treated on, than 
on the presence or absence of a supporting pedicle, which is given 
as the only diagnostic point of distinction between the two genera, 
Cothurnia and Vaginicola, as they at present exist. Neither can 
this distinction be accepted as a sound one, for though the long- 
stalked representatives of the first genus are distinct enough from 
the sessile Vaginicolse, yet every gradation may be met with 
between the two, until in specimens resembling the one to which 
my new species is attached in the illustration, it is by no means 
easy to decide in which genus they should be placed; the very 
faintest apology for a pedicle possibly exists, but even this, it might 
be suggested, might in the third or fourth generation be entirely 
dispensed with ; and more especially if called upon, as in the illus- 
tration, to act the part of foster-parent, by supporting the successive 
