ON THE RADIOL ARIA AS AN ORDER OF THE PROTOZOA. 373 
shell . He considers, therefore, that 4 it is not an organ,’ and 
certainly not 4 a generative organ ! ’ ” 
I shall now proceed to bring these lengthy, though I trust 
not altogether fruitless observations of mine to a close, by 
sketching as a supplement to my arrangement of the Rhizopods 
generally, the classification and characters by means of which 
the principal subdivisions of the polycystina, and every indi- 
vidual comprised within them, may, with a little care, he recog- 
nized and identified at any stage of their history, whether in 
their recent or their fossil condition. (See pp. 374, 375.) 
Order I. Herpnemata. — The primary and secondary cha- 
racters of this order are as follows : — No definite nucleus. No 
contractile vesicle. Sarcode without any permanent differentia- 
tion into endosarc and ectosarc, but consisting of purely homo- 
geneous, almost colourless, glairy basal Sarcode, within which 
granular particles, representing 44 formed material ,” of more 
consolidated texture than the basal sarcode, and of which the 
sarcoblasts or yellow reproductive bodies, constituting in the 
Herpnemata , the sole representatives of the nucleus which is 
present in the two higher orders, are mainly built up. Pseudo- 
podia numerous, more or less irregular, and forming frequent 
anastomoses, and exhibiting when projected the characteristic 
phenomena of pseudo-cyclosis. Both in the Foraminifera and 
Polycystina , when in an active living condition, the exterior of 
the shells is invariably enveloped by a delicate film of the basal 
sarcode. Shell or test, in the Foraminifera , either calcareous 
and deposited in a crystalline state; or having a calcareous 
basis into which are impacted mineral particles selected from 
without by the animal. In the Polycystina , the mineral por- 
tion, which may rather be regarded as an internal framework or 
skeleton than a true shell, is invariably siliceous, and throughout 
formed into one continuous piece. (See Explanation of Plate VI., 
Figs. 1, 2, 3 & 5.) 
Order II. Protodermata. — Definite nucleus present ; nuclear 
mass presenting a nucleolus, and enveloped in a distinct and 
firm membranous capsule . Sarcode somewhat more differen- 
tiated in appearance, but only in so far as the granular particles 
are, generally speaking, more closely confined to the central 
region. Pseudopodia never so numerous as in the Herpnemata ; 
more rigid and tapering, and only rarely sending off branches 
from one to the other. Reproduction by sarcoblasts ; * which 
are to be seen in the general mass of the body-substance, and, 
occasionally, within the nuclear capsule. These are, as in the 
Herpnemata , of a yellow colour. 
In the Plagiacanthidce or first family of the Protodermata , 
the name of which I take from the Plagiacantha arachnoides 
* From a-ap^j 'flesh, and pXdo-Trj, a growth or bud. 
