44 THE OYSTER. 



inner surface of one to that of the other, and firmly attached 

 to both, and these are called the abductor muscles, because 

 their office is to draw or pull; how strongly they do this 

 those whose business it is to open Oysters can best tell; if 

 the animal within were not alive, the process would not be 

 a difficult one, as in that case the muscles would be relaxed, 

 and the shell would come open of itself, so that actually 

 people who eat Oysters directly they are opened, swallow 

 them ''all alive-O!" 



If a pair of the shells from which the delicious morsel has 

 been extracted, be taken in the hand, it may be noticed that 

 one is much thinner, smoother, and flatter than the other; 

 this is the side most exposed to the action of the water; 

 the rougher and rounder side is that which is attached to 

 the rock, or other substance to which the animal forms an 

 attachment, that is usually life -long. The two portions of the 

 shell are joined together by a hinge of curious workmanship, 

 which is formed of the inner layer of the shell, and strength- 

 ened by a ligament which is wonderfully elastic; when the 

 shell is drawn together by the abductor muscles, the ligament 

 is at full stretch, and as soon as they relax at all, it con- 

 tracts, and causes the shell to gape. This process is repeated 

 as often as may be necessary for the safety and sustenance of 

 the animal within, whose mouth is situated at the narrowest 

 part of its habitation, namely, near the joint of the hinge, 

 which connects its upper and under shell. The anatomical 

 structure of the Oyster is more perfect than would be sup- 

 posed, from its apparently low state of organization; it has a 

 heart, liver, and intestinal canal, and a bag near the mouth, 

 which answers the purpose of a stomach. Its breathing organs 

 are gills, closely resembling those of most other fish; it has 

 little vessels which convey the bile from the stomach to the 

 liver, and may perhaps be subject to bilious attacks, as well 

 as those who swallow this cui'ious piece of organization at a 

 mouthful, without thinking at all of the goodly structure they 

 are demolishing. There is the tiny heart with its series of 

 blood-vessels, just as perfect as in the larger animals. There 

 are the nerves in the shape of minute feelers, which appear 

 to be acutely sensible not only of actual contact with foreign 

 bodies, but also of sounds and movements from without. A 



