Page:Evidence as to Man's Place in Nature.djvu/84

78 accurately, and only, at last, receives the touches which stamp its final character.

Thus, at length, the young puppy assumes such a form as is shewn in Fig. 14, C. In this condition it has a disproportionately large head, as dissimilar to that of a dog as the bud-like limbs are unlike his legs.

The remains of the yelk, which have not yet been applied to the nutrition and growth of the young animal, are contained in a sac attached to the rudimentary intestine, and termed the yelk sac, or umbilical vesicle.' Two membranous bags, intended to subserve respectively the protection and nutrition of the young creature, have been developed from the skin and from the under and hinder surface of the body; the former, the so-called amnion,' is a sac filled with fluid, which invests the whole body of the