66 THE OCEAN WORLD. 
a one as could be maintained. Neuremberg, Peyssonnel, and 
Trembley maintained the animal nature of sponges, and their views 
were adopted by Linnzeus, Guettard, Donati, Lamouroux, and Ehren- 
berg on the Continent, and by Ellis, Fleming, and Grant in England. 
Sponges live at the bottom of the seas in from 500 to 1,250 fathoms 
of water, among the clefts and crevices of the rocks, always adhering 
and attaching themselves, not only to inorganic bodies, but even 
growing on algz and animals, spreading, erect, or pendent, according 
to the body which supports them, and their natural habit. 
The power of fixing themselves to other objects, which certain 
animals possess, is very singular; nevertheless, it is certain that 
whole tribes exist, the species of which are strictly adherent, which 
live and die attached to some rock or other object, and among these 
are the sponges. It follows then that but for their cilia they would be 
wholly dependent on external agencies for their means of existence. 
“The poor little creatures,” says Alfred Frédol, ‘receive their 
nourishment from the wave which washes past them ; they inhale and 
respire the bitter water all their lives; they are insensible to that 
which is only the hundredth part of an inch from their mouth.” 
In the months of April and May these sponges develop ova 
which are round, yellow, or white, and from whence proceed certain 
ovoid granular embryos, furnished towards their largest extremity with 
small vibratile cilia. They are either carried off by the currents, or 
form swarms of larve round the parent sponge. They swim about 
with a gliding wavy motion, and when they have been some time in 
the water they usually come to the surface. During two or three 
days they seem to seek a convenient place to fix themselves. Once 
fixed, the larval form loses its cilia, spreads itself out, and soon grows 
into the form of its parent. 
“They soon attach themselves to some foreign body,” says M. 
Milne-Edwards, “and become henceforth immovable; no longer 
giving signs either of sensibility or of contractibilty, while in their 
enlargement they are completely transformed. The substance of 
their bodies is channelled and riddled with holes—the fibrous frame- 
work is completed—the sponge is formed.” 
Their interior organisation consists of contractile cellules and 
numerous spicula—‘a tribe,” says Gosse, “of the most debatable 
forms of life, long denied a right to stand in the animal ranks at all, 
and even still admitted there doubtingly and grudgingly by some 
_excellent naturalists. Yet such they certainly are, established beyond 
reasonable controversy as true and proper examples of animal life.” 
It may, indeed, be safely asserted that all naturalists are now 
