ment of the 
as Infusoria flagellata. 191 
to detect, even with a power of eight hundred diameters, not 
only because it is seldom at rest, but on account of its exces- 
sive delicacy ; yet when it does stop its vibrations, its charac- 
ter and proportions can be unequivocally demonstrated under 
the proper circumstances of illumination and adjustment. It 
is about twice as long as the body; and has a decided although 
not rapid taper at its distal termination. 
The mouth remains yet to be discovered. There can be no 
doubt, however, that it is an aperture of no very small extent, 
or at least that it is capable of considerable distention, inas- 
much as we find quite large angular particles within the body. 
That it is terminal rather than lateral, is probable from the 
similar position of this organ in the not very distantly allied 
genus Codosiga (§ 6). 
The two contractile vesicles (cv, cv) are situated midway be- 
tween the front and hind ends of the body, and at two nearly 
opposite points. ‘They are of moderate size, yet not so large 
as those of Codosiga (§ 6), which they resemble, but exhibit a 
much feebler action than the latter. 
The calyx (c! cc?), or carapace so called, has an ovate- 
campanulate outline, but is divided by a constriction into two 
regions. One of these, the basal (c*) or posterior third, is about 
one-half as wide as the remaining two-thirds (c), and possesses 
an ovate-obconical form, which tapers abruptly into the pedicel 
(pd). The anterior two-thirds (c) arises from the sharp con- 
striction with a strong swell or bulging, and then, narrowing 
a little, terminates with a truncate aperture (c!); so that on the 
whole this portion may be compared, in shape and proportions, 
to a claret-glass. This region is peculiar, moreover, in being 
longitudinally banded or sulcated by about twenty furrows, 
which terminate at the rim in as many notches, that alternate 
with a like number of distinct scallops. Of these two regions, 
the basal one is quite distinct, although perfectly hyaline ; but 
the banded part is much fainter, and requires a careful adjust- 
Night in order to bring it out clearly. The pedicel 
(pd) is moderately slender, colourless, at least as long as the 
ealyx, and of a uniform thickness from base to top. 
§ 6. CoposiGa, nov. gen.* 
Codosiga pulcherrima, nov. sp. Pl. V. figs. 7-27. 
This infusorian is as eminently a compound Flagellifer as 
Anthophysa (§ 11), and, although not a heteronematous form 
(like the latter), it bears a very striking general resemblance to 
it, as one may see by comparing figs. 8 and 47 with each other. 
* kadar, a bell; avyda, to be silent. 
14* 
