Pond life / by Edward C. Ash.

  • Edward C. Ash
Date:
[1913]
Catalogue details

Licence: In copyright

Credit: Pond life / by Edward C. Ash. Source: Wellcome Collection.

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    believe that the one-day-old tadpole, a creature more fish-like than frog-like, should turn into the stately and dignified Rana temporaria. During March and June, depending on the weather, frogs congregate at suitable ponds, often in hundreds. They come from all ways, sometimes travelling several miles. All the paths and. ruts leading to the meeting-place are alive with frogs, wandering slowly towards their destination. And the pond, which but yesterday contained only a few frogs, has now a teeming population, even the banks being covered. We will notice the male, which often seems ridiculously small, fastened upon the female, holding her under the arms. When once settled he has no wish to leave go, and seems to lose the power of liberating himself, even if he so wishes. For accidents do happen. In one case a pair so united fell a distance of four feet, and even that experience made no difference to the male, who remained calmly where he was. In the pond the female swims to and fro, carrying with her her inactive mate, who occasionally varies the monotony of the proceedings by uttering croaks. The eggs, which are fertilised by the female after they have left her body, are laid in a continuous string. Each egg is about x^th of an inch in diameter, and is covered by a sub- stance that by absorbing water swells to form the well-known jelly. No sooner have the eggs been fertilised than they show signs of life. In fact, the alterations in the embryo during the first few hours are remarkable. The owner of a microscope, if in- terested in embryology, may watch the changes taking place hour by hour. Six or seven days later the young tadpoles are no longer round but oval in shape, and very gradually, as time goes on, the oval becomes indented to form a head, body, and tail. Then two pairs of minute external gills, the eyes, a large ear, and a peculiar sucker beneath the head, makes an appearance. The embryo is now becoming tadpole-like, and is nearing the day when it will enter the world to start a life “on its own.” The young tadpole now shows signs of active life ; it no longer rests in the egg motionless, but moves occasionally. For a few more days it remains within its gelatinous sphere, becoming longer in shape and more active in disposition, until the day comes when it forces its way through the surrounding case, and escapes into the world. At first the young tadpoles, having no mouth, are unable to eat, but live on the remains of the yolk, as a chicken does for the first twenty-four hours after hatching. Two days later the
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