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.

    95/108 page 87
    Anodonta, the freshwater mussel, has a peculiar life history. The larvae hatch inside the parent, and remain there until tho end of the summer. They are then ejected, or perhaps leave on their own account, and swim about until they happen to meet a member of the pisces (fish); no sooner have they touched their unlucky host than they hold on to the best of their abilities, and remain until mature. Strangely enough, not only are they carried about by the fish, but also its skin grows so as to cover the parasitic mollusc, thus preventing it from dropping off should an accident occur. Snails’ eggs are so frequently found that they deserve men- tion. Molluscs are hermaphrodites—that is to say, both male and female in the same individual. On two snails meeting a peculiar battle takes place. In a sac kept for the sole and special purpose a number of darts are kept, and on this aus- picious occasion they are fired at each other by the molluscs. What the use of this conduct may be is difficult to say, as it hardly seems affectionate to hurl darts on such a trivial pre- text ; when this preliminary battle is over the two snails join together. It is interesting to know that one snail is tem- porarily male, whilst the other is temporarily female. The eggs are laid on sticks, stones, weeds, or the glass of the aquarium, in long jelly-like masses. The “ time being ” male, his work accomplished, now changes into a temporary female, and sub- sequently meets some other snail of the opposite sex, which will later in the season become a female. CHAPTER X FROGS A book on pond life would hardly be complete unless some pages were devoted to frogs and newts. Few people care to keep frogs except in a conservatory. Their incessant croaking, especially during the night, is far from pleasant, and owing to their surprising agility, sooner or later one or more frogs are certain to evacuate their home and perambulate the house, much to the horror of the gentler members of the household. How they have managed to escape is often a difficult question to solve. The life history of the frog is of particular interest, because the young are so very different to the adult. It is hard to
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