68 
Dr. Wallich_, on the Polycystina. 
not between either of the two Orders most closely related to 
each other. 
Now, this is a most important acknowledgment, if, as can 
be shown to be the case, the Rhizopod depicted be indeed of 
the Amoeban type. And I venture to hope that it will be 
recognised as confirming the views above expressed, inas- 
much as I am in a position to prove that, amongst the fresh- 
water Amcebans, examples occur in which,|whilst^the presence 
of a nucleus and contractile vesicle (even according to Dr. 
Carpenter^s own definition of his lowest type) exclude them 
from association with the Reticularia, and render it incum- 
bent on us to place them with Amoeba, the pseudopodia assume 
the mixed characters of the Actinophryna and Foraminifera 
precisely in the manner depicted in Schultze^s figure.^ 
Holding, as I do, these opinions concerning the value of 
the distinctive characters afforded by the substance of the 
sarcode, it naturally follows that I am disinclined to allow 
that the streaming of granules, both within the body of 
the Rhizopod and either along or within its pseudopodial 
extensions, is referable to a vital power resident in sarcode 
or the molecules suspended in it. I reject it, however, 
not because I desire to support a theory, but to establish 
the fact that, in every instance without exception, from 
the lowest to the highest type, the vital function j!?fi!r ex- 
cellence consists in the inherent contractility of proto- 
plasm, whilst the progression of the molecules simply 
becomes the exponent of that function. The contractility 
would seem to attain its maximum in Acanthometra and Eu- 
glypha ; but, as is well known, it is also signally observable in 
some of the Teoctularian Foraminifera of our own. shores. In 
all of these forms the instantaneous shooting-forth of the 
pseudopiari projections constitutes one of the most remark- 
able spectacles seen under the microscope ; its singular nature 
being, in a great measure, heightened from the circumstance 
that the action takes place even when the organism is confined 
between the glass slide and its cover. 
But in order to show that no trustworthy Ordinal character 
is deducible from this property — or, at any rate, none that 
has hitherto been made strictly available — it is only requisite 
to bear in mind that, by a sort of general consent, the Arnoe- 
ban type of protoplasm is considered as being that in which 
differentiation has proceeded to the furthest limits. Yet in 
Amoeba the purely secondary and incidental character of the 
* See my " Observations on the Amoeban Rhizopods," already referred to, 
as published in ' The Annals and Magazine of Natural Plistory' for June, 
1863, vol. xi, pi. X, figs. 4, 10 ; and for December of the same year, vol. xii, 
pi. viii, figs. 9-11, 12. 
