SPONGIA. 73 



They live at the bottom of the seas in five to twenty-five 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 vegetables 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 consisting of innumerable strictly adherent species, 

 which live and die attached to some rock or other object ; and among 

 these are all polypiers, such as the sponges and corallines. It follows 

 that they are wholly dependent on external agencies for their means 

 of existence. " The poor little creatures," says Alfred Fredol, " re- 

 ceive 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 animalcules engender 

 germs, round, yellow, or white, whence proceed certain ovoid granular 

 embryos furnished towards their largest extremity with small vibratile 

 cilia. They are thrown off by the currents, which serve as a stomach, 

 and form swarms of larvae round the polypier. They swim about 

 with a gliding wavy motion, and when they have been some time in 

 the water they usually come to the surface ; but they are also often 

 carried off by the current. During two or three days they seem to 

 seek a convenient place to fix themselves. Once fixed, the larvae 

 loses the cilia, spreads itself out, and takes the form of a flattened 

 gelatinous disk. 



Its interior organization consists of contractile cellules and numerous 

 spiculae " a tribe," says Gosse, " of the most debateable 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 natura- 

 lists. Yet such they certainly are, established beyond reasonable 

 controversy as true and proper examples of animal life." 



It may, then, be safely asserted that all naturalists are now satisfied 

 of the animal nature of sponges, although they represent the lowest 

 and most obscure grade of animal existence, and that so close to the 

 confines of the vegetable world, that it is difficult in some species to 

 determine whether they are on the one side or the other. " Several 



