66 



FIRST LESSONS IN ZOOLOGY. 



that of many other shell-fisii; and though it is less highly 

 developed (i.e., some of its organs less fully formed) than 

 they, yet they need not therefore despise the oyster, which 

 is superior to them in numbers and usefulness to man. 

 Happily oysters are not generally useful to fishes for food, 

 as their shells are rough and thick, so that skates, sharks, 

 and other fish find it " doesn't pay" to bother with them, 

 but burrow in the sand or mud after clams, mussels, and 

 other shells which they can get with less trouble. A good 

 many prettily painted bivalves, as the scallop, for example, 



FIG. 66. ^-Anatomy of the oyster, au, auricle; ve, ventricle; hm, body-mass; cl, 

 cloaca; </, gills; (' and i', intestine; /, liver, with its ducts opening into the 

 stomach; A/, adductor muscle; m, mouth; mt, mantle; o, the line of section 

 of Fig. 6" passing through the stomach ; p, outer wrinkled surface of inner or 

 lower palpi; r, vent. After Ryder. 



" look down" upon the lowly oyster; but as the latter has 

 no eyes, it probably has no pride, and is contented with its 

 rough exterior, and hides away from common observation, 

 mimicking rough stones and bits of shells, and in doing 

 this it is farther protected from the attacks of prowling 

 fish. So we see that the oyster, if it has no eyes, no foot, 

 and probably no ears, and even if its shell be, so to speak, 

 rough and carelessly made, without regard to looks, yet it 

 fills a large and important place in the economy of the 



