Dk. WallicHj on the Polycystina. 
69 
circulatory movement is most plainly demonstrable and univer- 
sally admitted, inasmuch as it may always be seen to follow 
the direction in which the contractile action would urge it, 
and to cease altogether when that action ceases. So that we 
are reduced to the dilemma of assuming — which would be 
absurd — that one kind of contractility is vested in Amoeba 
and another kind in the less differentiated genera ; or of allow- 
ing that the kind manifest in Amoeba must, a priori, be iden- 
tical (though not necessarily in degree) with that possessed 
by the other Ehizopods. 
Accordingly, if we revert to the classifications now pro- 
posed, we shall find that, assuming the characters of Lieber- 
kuhniaf^ and Pamphagus-^ to have been fully recorded by these 
discoverers, these organisms may be held to agree, in every 
essential respect, with the rest of the Herpnemata. In other 
words, supposing the existence of such a form as a naked 
Foraminifer or Polycystin, such form would, in all probability, 
be undistinguishable from Lieberkuhnia. For although true 
that, in the normal condition of this Rhizopod, the pseudopodia 
are more " indefinite that there is a more visible passage of 
granules within and along the substance of these processes ; 
and, lastly, that the apparent tendency to anastomose and 
form membrane-like expansions, is at a maximum ; there is 
every reason to believe that the differences observable between 
Lieberkuhnia and the testaceous families with v/hich it is asso- 
ciated through the negative character (common to all) of pos- 
sessing no nucleus or contractile vesicle, are due to the sar- 
code body being free in one case, whilst in the others the 
number, the direction, and the diameter of the pseudopodia, 
mainly depend on the position, the size, and the number of the 
apertures through which they have to pass. And I conceive 
this view is borne out by Carpenter^ s observation, that Arcella 
and Difflugia are nothing else than testaceous Amoebans 
and further by the opinion he expresses (although under the 
erroneous impression that no nucleus is present) that Gromia 
is '^^of essentially the same character as Lieberkuhnia.'' % 
I adduce these facts to show that, whilst confirming 
and following the classification of Dr. Carpenter in placing 
Lieberkuhnia and Pamphagus with the Foraminifera, I only 
extend the principle laid down by the same eminent 
authority when I associate the Polycystina with the Fora- 
* Discovered by MM. Claparede and Lachmann, and described in their 
* Etudes sur les Infusoires et les Rhizopods,' Geneva, 1858, pp. 464, 466. 
-f Discovered by the late Professor Bailey, of New York, and described 
by him in the * American Journal of Science and Arts,' vol. xv, reprinted in 
'Quarterly Journal of Microscopical Science,' vol. i, p. 295. 
X 'Introduction to the Study of Foraminiiera,' pp. 27 and 29. 
