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most naturalists, they had settled down into undoubted animals, 
technically called Zoriferz or pore-bearers, from the circumstance of 
their surfaces being covered all over with pores or openings. 
The sponge of commerce was not the animal, but only a part of 
the animal structure, the skeleton, according to the nature of which 
sponges were roughly classified into #erafose or horny, siliceous or 
flinty, and calcareous or limy sponges. The forms with which we 
were most familiar were the horny, the skeletons of which were found 
so useful and were of great commercial value. Among some of the 
most striking of the flinty sponges were the exquisite Venus’ flower 
basket, the sea-bird’s nest, and the glass rope, the last-named tor 
some time a bone of contention among naturalists, until the whole 
sponge was obtained. Most sponges might be said to consist of three 
distinct parts; the skeleton, the living part, and the spicules. The 
living part, called sarcode, was a glairy gelatinous substance about the 
same consistence as the white of an egg, of different colours, and 
composed of a granular substance similar to that simple organism, the 
Amzeba, which in the living sponge enveloped and permeated the 
whole structure ; portions of it were ciliated, and by means of these 
cilize, a circulation was kept up. This living sarcode secreted from its 
food material for re-formation, building up the skeleton and the forma- 
tion of the bodies called spicules. 
The spicules were composed either of silex or lime, and either 
formed, as it were, supports to the skeleton, or, as in the case of some 
of the siliceous sponges, served as a means of anchoring the animal. 
Microscopically considered, the spicules presented a very varied and 
beautiful series of objects of every conceivable combination of needle- 
like bodies, and would seem in many, if not all, to be not only invested 
but penetrated by thesarcode. Inthesiliceous sponges, and especially 
the anchoring ones, they were built up of successive layers of deposit, 
a fractured end presenting an appearance similar to a series of tubes 
as seen in a-telescope. ’ 
The holes or pores in the skeleton were of two kinds—those which 
took in currents of water, and those larger ones called osezda, from 
which currents containing effete matter were ejected. So great was 
the reparative power among sponges that if, as had been proved by 
experiments by Bowerbank, a living sponge be cut in half and the parts 
brought together under water, in 24 hours all trace of cutting would be 
effaced ; nay, if a piece were cut outof a living sponge and inverted so 
