. Contributions to the natural history of the United States of America. Zoology; Chelonia (Genus); Ctenophora; Cnidaria; Animals. Fig. 9. diverts its course, forming there a narrow cavity {Fig. 2, e c^). At this early period the medusa-bud has the power of extending and distending itself, to a o-peat length and breadth, so as to be at one time twice (PL XVIII. Fie/. .3) or thrice as large as at other times. The simple hernia-like state is soon superseded by '"' '' ^'^' ^' one which offers unmistakable evidences of the medusoid nature of these buds (PL XVIII. Fiffs. 4, 5, 6, and 7, and woo
. Contributions to the natural history of the United States of America. Zoology; Chelonia (Genus); Ctenophora; Cnidaria; Animals. Fig. 9. diverts its course, forming there a narrow cavity {Fig. 2, e c^). At this early period the medusa-bud has the power of extending and distending itself, to a o-peat length and breadth, so as to be at one time twice (PL XVIII. Fie/. .3) or thrice as large as at other times. The simple hernia-like state is soon superseded by '"' '' ^'^' ^' one which offers unmistakable evidences of the medusoid nature of these buds (PL XVIII. Fiffs. 4, 5, 6, and 7, and wood- cuts 7, 8, and 9). Taking the simplest view of this stage, at the plane of the axis, as if the bud were split longitudi- nally into halves, we may see that the inner wall (PL XVIII. Fig. 7, c) has reverted upon itself, and assumed a cup-shaped form, the hollow of which forms a close-fitting receptacle, or mould, as it were, for the thickening (d^) of the under side of the outer wall. By receding from this point of view, toward the surface of the bud (PL XVIII. Fig. 5, and wood-cut 8), the rim (/i) of the cup comes into sight. In consequence of the re- version of the inner wall upon itself, the cup naturally is formed of a double layer {Fig. 6, wood-cut 9, c' c-^, and Fiff. 7). In doubling upon itself, the retreating fold (c^) does not press closely, at all points, upon the stationary one (c), but leaves four equi- distant spaces, into which the chymiferous fluid penetrates. This gives the cup a four-lobed appearance, each lobe (Fig. 4 and wood-cuts 7, c c^ (^ c% and 8, c c^) containing a chymiferous channel (ch). When seen from a point opposite the end of the bud, all four channelled lobes (wood-cut 10, c c^ c^ c^) come into view at once, standing at four equidistant points, ninety degrees from each other, around the cup. Between the lobes, the wall {iiv) is single, and, on account of the thickness and dark color of the lobes, not easily recognized in profile, but, as we hav
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Keywords: ., bookcentury1800, bookdeca, booksubjectanimals, booksubjectzoology
