H. J. Clark on the animality of Spoages. 323 
to a stem, is an adult; and more especially so since, among many 
hundreds which I have observed from time to time, I have never 
seen any trace of a transition to a higher form. That such 
simple organizations can exist without rising toa more compli- 
cated state, during a whole lifetime, I am furthermore sustained 
in believing by the discovery of some new generic forms, which, 
although scarcely, if at all, more highly organized than Monas, 
have in addition such characters as would seem to stand in the 
way of a transition to a more elevated grade of existence. For 
instance, the presence of a calyx about the body of an infusorian, 
into which it can retreat, is an indication of a fixity of condi- 
tion which corresponds to the adult state. Thus I found one of 
the new genera which I just alluded to. : 
Bicoseeca, as it is called, may be described in general terms as 
a stemless Monas which is attached to the bottom of a calyx, by 
a highly muscular, retractile cord. All the organs have the same 
remarkable definiteness of relationship and peculiarity of form 
that Monas possesses; and in addition there is the muscular cord 
which, with oft-repeated jerks retracts the body to the very bot- 
tom of the calycine envelope. ere are two singularly diverse 
species of this genus; one marine and the other lacustrine. - 
The most interesting infusorian of this group of new forms is 
the one which I have called Codosiga. This links the Sponges to 
the flagellate Infusoria. Its greatest peculiarity consists in the 
Sapien of a highly flexible, extensible and retractile, nem- 
ranous collar, or hollow cylinder, which projects from the an- 
terior end of the body. The cylinder is slightly flaring, and, if 
we include the asymmetrical body, the whole might be compared 
toa very deep, one-sided bell, with its narrower end half filled 
up. The single, sigmoid-arcuate, rigid flugellum arises from the 
depths of the bell, exactly at the middle of the truncate front, 
as it were forming a prolongation of the longitudinal axis of the 
y- There is no lip, and the flagellum, which rises close to 
the mouth, has a strong resemblance to that of Monas, both in 
proportion, form, and habits; and performs the office of a pre- 
hensile organ when the body is fixed, or acts as a propeller dur- 
ing natation. ‘The contractile vesicles are two, or even three, in 
number, and lie in the posterior third of the body. The only 
Species of this genus which I know of is gregarious in habit, 
but usually not more than four or five bodies are to be found at- 
tached, like Anthophysa, by their narrower, posterior ends, to 
the branchlets of a single forking stem. The peculiarity in re- 
gard to the direction of the curvature of the flagella in a back- 
ward direction, toward the stem, is as highly marked in Codosiga 
as in Anthophysa (described by me in the September number 
of this Journal) and there is also the same fixed relationship of 
the longitudinal and the’ greater and less transverse d 
of the several individuals of the colony. 
