_Fig. 24._ SPONGES. ] “Indeed I do,” said Mrs. Merton, “for though sponge was once supposed to be a marine plant, it has long since been discovered to be an animal. About the year 1752 a gentleman, named Ellis, was at Brighton forming a collection of marine plants for the instruction of some part of the Royal Family in botany, and amongst other things he collected some curious specimens of sponges, which he examined through a powerful microscope with a view to obtain a knowledge of some peculiarities which he considered necessary to be ascertained before they could be properly classified. By this examination he discovered that the sponges possessed a system of vessels through which the sea-water circulated, and which opened by means of innumerable pores. Subsequent examinations proved that what we call sponge may be compared to the shell of the snail or the oyster, and that it acts as a covering to the jelly-like animal or animals which reside in it, being as necessary to them as shells are to the molluscous animals. Mr. Ellis, after making these discoveries, examined different kinds of coral, and found that they were also furnished with pores containing animals, the tentacula or feelers of which were continually expanding and contracting as if seeking and seizing prey.” “How very curious!” cried Agnes; “and what do these creatures live upon?” “Probably,” returned her mamma, “on some animalcules contained in the water, the forms of which are too minute to be visible to human eyes even though aided by powerful microscopes.” “I can easily imagine they must be very small,” said Agnes, “as the creatures which feed upon them are so little themselves. But I think I have seen the pores in the coral.” “I have no doubt you have,” said Mrs. Merton; “the pores in some of the kinds of sponge are also quite large enough to be visible to the naked eye.” “But where is sponge found, mamma?” asked Agnes. “It is generally collected from rocks in the sea,” replied Mrs. Merton, “about twenty or thirty feet deep, by divers, who in time become very expert in obtaining it. It grows so rapidly, that it is said rocks have been found covered with it that were completely cleared only two years before.” “What kinds of coral are these mamma?” said Agnes, picking up two or three pieces which lay upon the stall. [Illustration: _Fig. 25._ CORALS. ] “I do not know the names of all of them,” said Mrs. Merton; “but I believe that kind which looks as though it were formed of small beads is called the chain coral, or Catenipora; and that other kind which appears covered with star-like flowers is called Aulopora.” [Illustration: _Fig. 26._ SADDLE-SHAPED ANOMIA. ]