The animal kingdom : arranged after its organization, forming a natural history of animals, and an introduction to comparative anatomy . Fio. 7.—Dev OFMkDIia; a, h,e,tpolypiiid growth. view of the stage j. Now in this condition, the animal is in every essential particular, a true Polype; and hasbeen repeatedly so described. It remains attached by its base to one spot, draws its food into its mouth bymeans of its arms, and these contract when the stomach is distended, and cannot then be irritated to only docs it live as a Polype, but it also reproduces itself as a polype ; for poly
The animal kingdom : arranged after its organization, forming a natural history of animals, and an introduction to comparative anatomy . Fio. 7.—Dev OFMkDIia; a, h,e,tpolypiiid growth. view of the stage j. Now in this condition, the animal is in every essential particular, a true Polype; and hasbeen repeatedly so described. It remains attached by its base to one spot, draws its food into its mouth bymeans of its arms, and these contract when the stomach is distended, and cannot then be irritated to only docs it live as a Polype, but it also reproduces itself as a polype ; for polype-buds are not unfrequentlyseen to issue from its sides (Fig. 7,1); these become detached and form new individuals, just as in the Hydra. Thusfrom a single individual, a whole colony may be produced ; and these may all continue in the polypoid conditionfor many months, or even years. But under some peculiar circumstances, whose nature has not yet been deter-mined, an entirely new series of changes at last takes place. The body assumes a more elongated cylindrical form RADIATA. 697. than it previously possessed ; and a constriction or indentation is seen around tliis cylinder, Just below tne rin)*tluit surrounds the mouth and gives origin to the tentncula (Kig. 8, a.) Similar constrictions are soon rt-puutvdaround the lower parts of tlie cylinder, so as to give to tlio wholebomewhat the appearance of a rouleau of coins (b). Still, how-ever, a sort of fleshy bulb,—somewhat in the form of the originalpolype, is left at the base. The number of tlie circles is , and all are not formed at once ; now constrictions appear-ing below, after the upper portions have been detached. Asmany as twenty-seven disks Iiavo thus been progressively sepa-rated in one animal. The constrictlunfi then gradually deepen,so as almost to divide the cylinder Into a pile of distinct saucer-liko bodies ; the divisions being most complete above, and theupper disks often presenting a considerable
Size: 1228px × 2035px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorwe, bookcentury1800, bookdecade1840, booksubjectanimals
