. Lehrbuch der Embryologie. Embryologie. 460 EMBRYOLOGIE DER UNTEREN WIRBELTIERE Oh.. Abb. 208. - PlujU,, malum hypochondrialis, Weibchen, die Männchen auf dem Rücken während der Eiablage. (Nach Budgett, 1899..) behalten ihre Form Trichter. Die Eier entwickeln sich innerhalb der Gelee bis die Bühne oi' eine Kaulquappe von 9-10 mm in der Länge. Während dieses Prozesses wird das Gelee anscheinend verflüssigt, bis nur noch eine dünne membranöse Beutel mit wäßrigen Flüssigkeit jeder Embryo umgibt. Schließlich die Überreste der Gelee mit den darin enthaltenen Kaulquappen sickert nach unten ins Wasser. Wenn, wie dies manchmal, die Marge des Wasser ha

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. Text-book of embryology. Embryology. 460 EMBRYOLOGY OF THE LOWER VERTEBRATES oh.. Fig. 208. — PlujU, , malum hypochondrialis, female carrying male on her back during oviposition. (After Budgett, 1899..) retain its funnel shape. The eggs develop within the jelly up till the stage oi' a tadpole of 9-10 mm. in length. During this process the jelly apparently liquefies, until only a thin membranous bag containing watery fluid surrounds each embryo. Eventually the remains of the jelly with its contained tadpoles trickles downwards into the water. If, as sometimes happens, the margin of the water has retreated from immediately below the leaf the tadpoles may still make their way for a distance of several inches to the pool by active jumping movements, helped it may be by a shower of rain. In the allied Phyllomedusa sauvagii, from the same neighbourhood, a similar mode of oviposition occurs, though here the nest is composed of several leaves (Fig. 209). Agar (1909) finds in this case that both at the commencement and end of oviposition there are laid a large number of spheres of jelly which contain no egg in their interior.1 The eggs are thus protected both above and below by a thick mass of eggless spheres. During the later stages of development the layer of envelope next the surface of each egg becomes greatly distended by the accumulation of fluid within it, the jelly between the eggs meanwhile diminishing in volume. The larvae with their huge external gills have thus considerable room in which to move freely. Eventually the envelope ruptures and the larva hatches. The nest thus comes to be occupied by a seething mass of tadpoles, floored and roofed in by a thick mass of jelly formed by the empty spheres. Eventually — in from 12-24 hours after the bulk of the larvae have hatched—the jelly begins to deliquesce and the larvae drop down with it into the water. Similar nesting habits occur in other tropical Hylids, e.g. Phyllo- 1 In the common Frog {liana temporaria)

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• bookcentury1900
• bookdecade1910
• bookpubli
• booksubjectembryology