T)r. Wallich^ on the Polycystina. 
65 
It will be seen that, in these definitions, all reference to 
characters derived from the degree of apparent differentiation 
presented by the sarcode mass and pseudopodia is rigidly 
excluded. This circumstance demands explanation. 
Those acquainted with the physiological phenomena 
ascribed to the Rhizopods are well aware that processes similar 
in result, if not identical in their mode of operation, with 
those on which the life of the higher orders of animals 
depends, are stated to be observable. Carpenter's graphic 
description of these phenomena must, indeed, be familiar to 
every one. Nevertheless, it appears to me that we have 
been going a little too far in taking for granted all that has 
been asserted on the subject, and have allowed theory so far 
to take precedence of actual demonstration that lines of de- 
marcation between the varying degrees of consolidation of 
the ectosarc, as compared with the endosarc, have been 
drawn, which further acquaintance with the E-hizopod proves 
to be untenable. In a paper such as this it is desirable to 
avoid all mere speculation. But the fact I am about to 
adduce seems of such importance as to warrant the con- 
clusion that, although the Amoeban and Actinophryan fami- 
lies do unquestionably incept solid food-particles, digesting 
and assimilating whatever portions are nutritious, and 
extruding the remainder, it by no means follows that all the 
lower families derive their sustenance after the same fashion. 
For, during many years' study of the Foraminif era, Poly cystina, 
Acanthometi'ina, Thalassicollina, and Dictyochidm (all pelagic 
lihizopods), in their living condition, notwithstanding a keen 
look-out for an example, I have invariably failed to discover 
a single instance in which there was satisfactory evidence 
that solid matter had been taken into the substance of the 
body as food. This fact derives additional weight from the 
circumstance that some of these Rhizopods occur at times in 
immense numbers. It is difficult, therefore, to conceive 
how all should present themselves devoid of everything like 
solid incepted matter, were such matter essential to their 
sustenance. For it must be manifest that, as generally 
attributed to the Rhizopod, the processes referred to partake 
of the miraculous J and, what is particulary notable, that 
it is not amongst the highest members of the class that these 
processes seem to be carried on in the absence of organs 
wherewith to effect them, but in those lower types in which 
we have hitherto failed to detect a trace of such organs. 
I am compelled, therefore, although by no means on this 
solitary ground, to dissent from Dr. Carpenter's views re- 
garding the value to be assigned to the differentiation of 
