. The microscope and its revelations. asto appear only like littletubercles around its en-trance. By means ofthese instruments theHydra is enabled todraw its support fromanimals whose activity, as compared with its i • i .L f own slight powers ot locomotion, might havebeen supposed to re-move them altogetherfrom its reach ; forwhen, in its movementsthrough the water, aminute worm or a. water-flea happens to touchone of the tentacles of the polype, spread out as these are in readiness for prey, it isimmediately seized by this; other arms are soon coiled around it,and the unfortunate victim is s
. The microscope and its revelations. asto appear only like littletubercles around its en-trance. By means ofthese instruments theHydra is enabled todraw its support fromanimals whose activity, as compared with its i • i .L f own slight powers ot locomotion, might havebeen supposed to re-move them altogetherfrom its reach ; forwhen, in its movementsthrough the water, aminute worm or a. water-flea happens to touchone of the tentacles of the polype, spread out as these are in readiness for prey, it isimmediately seized by this; other arms are soon coiled around it,and the unfortunate victim is speedily conveyed to the stomach,within which it may frequently be seen to continue moving forsome little time. 80011, however, its struggles cease, and its outlineis obscured by a turbid film, which gradually thickens, so that atlast its form is wholly lost. The soft parts are soon completely dis-solved, and the harder indigestible portions are rejected through themouth. A second orifice has been observed at the lower extremity 3 K. FIG. 659.—Ga/nvpanulafia gelatinosit. 866 SPONGES AND ZOOPHYTES of the stomach; but this would not seem to he properly regarded asanal, since it is not used for the discharge of such exuviae; it isprobably rather to be considered as representing, in the Hydra, theentrance to that ramifying cavity which, in the compound Hijdrozoa,brings into mutual connection the lower extremities of the stomachsof all the individual polypes. The ordinary mode of reproduction in this animal is by a gemma -tion resembling that of plants. Little bud-like processes (fig. 658,b, c) developed from its external surface gradually come to resemblethe parent in character, and to possess a digestive sac, mouth, andtentacles ; for a long time, however, their cavity is connected withthat of the parent, but at last the communication is cut off by the closure of the canal of the foot-stalk, and the young polype quitsits attachment and goes in questof its own maintenance. Aseco
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