392 Royal Society : — On the Distribution of 



other animals. All the rest are therefore non-parasitic, deriving 

 their sustenance from the outer world. If we now consider 

 the manner in which nutritious matters are taken up and assimi- 

 lated by these animals, we find that some of them must subsist 

 on organic substances in solution, which are absorbed by the 

 general surface of the body. Moreover we observe that this 

 takes place either indirectly through a more or less consistent 

 investijig substance, or directly through the pores, foramina, or 

 fenestrations of the calcareous or siliceous capsules protecting 

 the contained sarcode bodies. In other instances, on the contrary, 

 solid food is actually consumed by mouthless beings, which simply 

 open their bodies to receive it; and this opening of the body 

 may take place at any part of the surface most convenient, or 

 it may be restricted to a definite locality, shadowing forth the 

 permanent mouth of the Stomatoda, or even that of the most 

 primitive form of Hydrozoa. 



The annexed Table of arrangement is drawn up in accordance 

 with the foregoing remarks. 



Physiological Classification of the Protozoa. 

 Habit of life and mode of nutrition : — 



I. Parasitic Gregarinidce. 



II. Non-parasitic. 



A. Assuming food in a state of solution by absorption 



of the general surface. 



1. Indirectly through a medium 



a. Forming a cell -like envelope Thalassicollidts. 



b. Lining porous canals in the common mass . . . Porifera. 



2. Directly through 



a. The pores or foramina of a calcareous shell . . . Foraminifera, 



b. Fenestrations of a siliceous shell Polycystina. 



c. A more largely exposed surface AcanthometridcB. 



B. Assuming solid food by an adventitious mouth. 



1. At any part of the surface where the contact 



is made Monera, Aiimba, ^c. 



2. At a definite part, determined by the opening 



of the shell Gromia, Biffltigia, ^x. 



C. Assuming solid food by a permanent mouth, 



1. The same orifice being also excretory Infusoria. 



2. Discharging excreta by a rudimentary anus NoctilucideB. 



This Table may be said to afford us good general grounds for 

 forming an estimate of the relatiAe superiority of the several types 

 thus physiologically defined, and it is mainly in keeping with 

 their more commonly received distribution founded on structural 

 particulars. 



A show of progressive improvement is seen in the respective 

 sections A, B, and C — though to all appearance the simplest 

 group of animals in existence, namely the Monera of Hiickel, is 

 included in the section B. These rudimentary creatures are 

 destitute of both nucleus and contractile vesicle, though exhibiting 

 activities in movement, taking food, and reproducing their kind, 

 not eA^en second to those of Amoeba and its allies. The smallest 

 ciliated molecule endowed with animal life could not present a 



