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Page:Popular Science Monthly Volume 38.djvu/75

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are of an oval shape, 1·28 inch long and ·91 inch in diameter. When carefully blown they will retain their form. The shell is very hydroscopic, and, if the eggs be placed in alcohol or glycerin, they soon shrivel, owing to the abstraction of water from the interior. The young hatch late in October, just in time to move into winter quarters.

The disposition of our box tortoise is timid and gentle. If kept for a pet, it soon becomes very tame, and will eat from the hand of its master, whom it may even grow to recognize. In captivity it displays a great variety of tastes, and will readily take to cooked meat, vegetables, or bread.

Of all the lower vertebrates the tortoises exhibit, perhaps, the most marvelous regularity in their habits.

Thus the duration of the laying period is a very short time, usually in June, and rarely extending over two weeks for each species. It seems to be independent of the severity or mildness of the season, but occurs with wonderful regularity year after year. The same rule seems to apply to the time of hibernation. Seven young tortoises of various species, which were kept in an aquarium in a warm room, simultaneously refused to eat on the 5th of October, and went into hibernation just as they would have done if in the open air. They remained buried in the mud beneath the water, or huddled up asleep upon the land, and touched no food for over two months. Sometimes, when the aquarium was exposed to the full heat of the sun, one or two would awaken and crawl slowly about, but it was extremely difficult to induce them to eat.

A turtle's heart consists of two auricles and only one ventricle; so, the blood is never completely aerated and is therefore, comparatively speaking, "cold." This is the reason that tortoises, especially those species which inhabit our rivers and ponds, delight to bask for hours, exposed to the full glare of the hottest sun.

Millions of years ago, when marshes covered the greater part of the face of the earth, the reptiles were of huge size and strength. The turtles of to-day are but the pygmy descendants of these giant ancestors. Protected by their bony coverings, or relying upon their knife-like jaws and savage dispositions, they have survived in stunted form until to-day. Now, in this age of man, many species bid fair to outlive the wanton destruction which is fast depriving our woods and meadows of the wild creatures which once knew them as a safe retreat. The beaver, the gray squirrel, the wild pigeon, will soon be no more; but the lover of nature may still find our tortoise for his study and amusement.