Essentials of Biology Presented in Problems
by Hunter
Format: Paperback
ISBN13: 9781152535947
Paperback|9781152535947
Out of Stock
Overview
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1911 edition. Excerpt: ...in this country aggregating over $1,000,000 yearly. The Blue Crab.--Another edible crustacean of considerable economic importance is the blue crab. Crabs are found inhabiting muddy bottoms; in such localities they are caught in great numbers in nets or traps baited with decaying meat. They are, indeed, among our most valuable sea scavengers, although they are carnivorous hunters as well. The body of the crab is short and broad, being flattened dorso-ventrally. The abdomen is much reduced in size. Usually it is carried close to the under surface of the cephalothorax; in the female the eggs are carried under its ventral surface, fastened to the rudimentary swimmerets in the position which is usual for other crustaceans. The young crabs differ considerably in form from the adult. They undergo a complete metamorphosis (change of form), and their method of life differs from the adult. Immediately after molting, crabs are greatly desired by man as an article of food. They are then known as " shedders," or soft-shelled crabs. Other Crabs.--Other crabs seen along the New York coast are the prettily colored lady crabs, often seen running along our sandy beaches at low tide; the fiddler crabs, interesting because of their burrows and gregarious habits; and perhaps most interesting of all, the hermit crabs. The edible blue crab. From photograph loaned by the American Museum of Natural History. Hermit crab, about twice natural size. From photograph loaned by the American Museum of Natural History. The hermit crabs use the shells of snails as homes. The abdomen is soft, and unprotected by a limy exoskeleton, and has adapted itself to its condi tions by curling around in the spiral snail shell, so that it has become asymmetrical. These tiny...
| ISBN-13 | 9781152535947 |
|---|---|
| ISBN-10 | 1152535943 |
| Weight | 0.85 Pounds |
| Dimensions | 9.00 x 6.00 x 0.59 In |
| List Price | $22.54 |
| Format | Paperback |
|---|---|
| Pages | 260 pages |
| Publisher | |
| Published On | 2010-01-01 |
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