Elements of biology; a practical Elements of biology; a practical text-book correlating botany, zoology, and human physiology elementsofbiolog00hunt Year: [c1907] 220 ZOOLOGY at nineteen. In this latter class are placed the crayfish, lobster, blue crab, shrimp, and most of our common crustaceans. The North American Lobster. — In structure it is almost the counterpart of its smaller cousin, the crayfish. Its geographical range is a strip of ocean bottom along our coast, estimated to vary from thirty to fifty miles in width. This strip extends from Labrador on the north to Delaware on the south
Elements of biology; a practical Elements of biology; a practical text-book correlating botany, zoology, and human physiology elementsofbiolog00hunt Year: [c1907] 220 ZOOLOGY at nineteen. In this latter class are placed the crayfish, lobster, blue crab, shrimp, and most of our common crustaceans. The North American Lobster. — In structure it is almost the counterpart of its smaller cousin, the crayfish. Its geographical range is a strip of ocean bottom along our coast, estimated to vary from thirty to fifty miles in width. This strip extends from Labrador on the north to Delaware on the south. The lobster is highly sensitive to changes in temperature. It migrates from deep to shallow water or vice versa according to the temperature of the water, which in winter is relatively warmer in deep water and cooler in shallows. Sudden changes in the water of a given locality may cause them to disappear from that place. The more abundant food supply near the shore also aids in determining the habitat of the lobster. Lobsters do not appear to migrate north and south along the coast. While little is known about their habits on the ocean bottom, it is thought that they con- struct burrows somewhat like the cray- fish, in which they pass part of the time. As they have the color of the bottom and as they pass much of their time among the weed- covered rocks, they are able to catch much living food, even active fishes falling prey to their formidable pinchers. They move around freely at night, usually remaining quiet during the day, especially when in shallow water. They eat some dead food; and thus, like the crayfish, they are scavengers. Development. — The female lobsters begin to lay eggs when about seven inches in length. Lobsters of this size lay in the neighborhood of five thousand eggs; this number is increased to about ten thousand in lobsters of moderate size (ten inches m North American Lobster. This specimen, preserved at the Fish Commission, was of un- usua
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