66 
which is often coloured, throws out its threadlike 
processes. The skeletons are of very delicate and 
varied forms, resembling helmets, bishop’s mitres, 
baskets, or bundles of arrows. Every conceivable 
shape is found among the Radzolaria, and they form 
a charming study. 
At Fig. u. Eucyrtidium cranoides, v. Acantha- 
stauras purpurascens, and Fig. w. Diploconus fasces 
Order II. 
These must generally be distinguished by their 
skeleton being formed of carbonate of lime; though 
some forms are without a skeleton. Here, too, the shells 
exhibit openings, through which the protoplasm of 
the animal protrudes. 
Fig. x. Polystomella strigilata is a living species, 
with a skeleton divided into chambers, and riddled 
with holes through which the protoplasmic threads 
project. 
Fig. y. Bulimina pupoides fig z. Globigerina 
conglomerata and fig. za, biloculina ringens are three 
more hiyhly magnified skeletons of Foraminifera, 
which form the chief constituant of common chalk. 
Thus these microscopic creatures play at least as 
great a part in the formation of the world as the 
coral animal themselves. And they still swim by 
myriads at a moderate depth in the sea, and their 
shells sink to the bottom in heaps in the ‘“Globi- 


three forms of skeleton are shown, with the accom- 
panying animal throwing out its radiating processes. 
It most not be forgotten that all these figures are 
highly magnified, and that the originals are of mi- 
croscopic dimensions 
The Radziolaria are marine animals, and their 
remains cover vast spaces of the bed of the ocean, 
frequently at an immense depth. 
Foraminifera. 
gerina Zone” of the Atlantic, to form the chalk de- 
posits of future ages. 
Fig. zb. Amoeba princeps has no skeleton and 
no fixed form, but is always changing its shape. 
These simple cells are formed in damp mud, and 
stand not only at the very lowest point in the animal 
kingdom, but at the actual limit between the animal 
and vegetable kingdoms, which are no longer se- 
parable in their lowest forms, so far as our present 
knowledge extends. Many low animals and plants, 
as well as many cells in the higher animals, exhibit 
the same characters as the Amoeba, in their earliest 
stage. Thus it is not only the first link in the 
long clain of animal organisms, but is also the 
foundation-stone on which the whole of organic 
nature is reared; itself so varied in its innumerable 
forms, and yet possessing an indivisible unity, 
ENE 2 
ra 

