Definitions

from The Century Dictionary.

  • noun The umbilical vesicle (which see, under vesicle). Also called yolkbag. See cuts under embryo and uterus.

Etymologies

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Examples

  • In its ball-like form and short thick peduncle, the yolk-sac of Centrophorus agrees with Squalus, and differs greatly from that of Galeus, which I have described as of peculiar shape, provided with a long umbilical cord, entering the sac towards the larger end.

    Notes on New Zealand Fish

  • They are all of similar size, being 165 mm. in length, but had evidently not nearly reached their full foetal development, as the yolk-sac is large 66 mm. in diameter and almost globular.

    Notes on New Zealand Fish

  • This yolk-sac allows the alevin to attain a relatively large size in the first month or so of its life and eliminates the total dependence on feeding.

    Trout and Salmon of North America

  • This yolk-sac allows the alevin to attain a relatively large size in the first month or so of its life and eliminates the total dependence on feeding.

    Trout and Salmon of North America

  • This yolk-sac allows the alevin to attain a relatively large size in the first month or so of its life and eliminates the total dependence on feeding.

    Trout and Salmon of North America

  • This yolk-sac allows the alevin to attain a relatively large size in the first month or so of its life and eliminates the total dependence on feeding.

    Trout and Salmon of North America

  • It was known by the 1860's that various nutritive, respiratory, and excretory organs (yolk-sac, allantois) characteristic of embryos are lacking in all adults.

    RECAPITULATION

  • _Philozoon_ (far better than a yolk-sac) survive a fortnight or more in

    Scientific American Supplement, No. 324, March 18, 1882

  • On developing this bubble they are unable to stay at the bottom as they usually do, but swim about on their backs at the surface, with part of the yolk-sac out of the water.

    Amateur Fish Culture

  • When hatched out and kept in water containing a very large quantity of air in solution, I found that sometimes alevins developed an air bubble in the yolk-sac.

    Amateur Fish Culture

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