SPONGES AND ANIMALCULES 367 
of flinty fibres that may be over a foot in height. 
One of the compound or social sea-anemones is in 
the habit of forming bark-like encrustations on this 
glassy stem, and it was for a long time doubtful whether 
the sea-anemone or the sponge produced the support- 
ing-stalk, 
The ANIMALCULES, which represent the simplest 
and lowest forms of living animals, consist chiefly of 
organisms which are the equivalents of one of the 
single cells, or, as they might be termed, the 
“Vife-bricks,” out of which all the higher animals, 
and also plants, are built up. They are of minute 
dimensions, and require the aid of the microscope 
for their proper investigation. Among the most 
highly organised members of this sub-kingdom 
mention must be made of the CILIATED ANIMALCULES, 
or INFU- 
SORTA, 
socalled 
because 
toh ey 
were 
first dis- 
covered 
inhabit- 
ing de- 
caying 
vege- 
ta ise 
and ani- 
mal in- 
fusions. 
The so- 
called 
amazing 
which represent its organs of locomotion. 
Photo by W, Savilie-Kent, F.Z.S.] [ Milford-on-Sea 
PORTUGUESE BIRD’S-NEST SPONGE 
Dredged from a depth of 600 fathoms off the coast of 
Portugal, In life the be dy, oF ft cup,” of this 
sponge was deep orange colour, from which 
the grey beard-like mass of anc horing 
fibres dk pended 
SLIPPER-ANIMALCULE is one of the commonest 
forms which makes its appearance amidst such 
environments. The length of this single-celled 
animal scarcely averages the one-hundredth part 
of an inch, but within this restricted space an 
degree of structural and functional 
differentiation is included. Its outer surface 
is, in the first place, densely clothed with hairs, 
This 
outer cell-wall has a subjacent somewhat softer 
layer, in which are developed as crowded a series 
(as compared with the hairs) of minute rod-like 
bodies, which, under various stimuli, can be shot 
out like darts through the skin, and are adjudged 
to be offensive and defensive weapons, partaking 
Photo by E. Connsld] [st. Leonards much of the same nature as the thread- or 
CHALINA SPONGE stinging-cells of sea-anemones. Among other 
Composed partly of horny and partly of finty elements noteworthy structures, the  slipper-animalcule 
