MOLLUSCA. 



Braziliau l ap-a. 



Scallop. 



Common Ouster. 



base of the triangle at their margin ; the shortest side contains the ligament, that is, the hinder part of the 

 shell; whereas, in bivalves, generally, the hinder part is longest. This genus is widely diffused, some 

 species of it existing in all seas. They lie buried in sand or mud, with the short end of the shell upper- 

 most, that water may enter through the breathing syphon. 



In the annexed plate are represented the hinge and interior of the valves of the Donax Scortum. The 

 fossil species of this genus are few, occurring chiefly in the blue marls of southern France, and in the 

 oolite series. 



The Variegated Amphidesma is a species native to the Brazilian coast. Five fossil species are recorded 

 by Phillips, as found in the oolite group. 



The Common Crassatella comprises ten or twelve known species. It would seem to belong to the shores 

 of America, having been there dredged up from sandy mud in eleven fathoms water. Fossil species of this 

 mollusc are found in the London clay, and in the calcaire grossiere of Paris. 



The Scallop belongs to the family of Pectens, or Pectenidse. Like the Oyster, it is two-shelled. These 

 two shells are united by a powerful and exceedingly elastic hinge. In addition, the animal is provided with 

 a very powerful muscle, obedient to its will, by means of which it may, at pleasure, open its valves or keep 

 them firmly shut. The Scallop employs the rapid opening and shutting of its shells, as a means of loco- 

 motion. This creature is found in the European seas, and along the southern coasts of England. All may 

 remember, the Scallop-shell was used, in the middle ages, as the badge of a pilgrim to the Holy Land 



The Common Oyster has been for many ages considered as a delicacy for the table. In the times of the 

 ancient Romans, we find that the native English Oysters were exported to Rome, and there placed in the 

 Lucrine Lake, where they were fattened. On the coast of England, the Oysters breed in large beds, to 

 which vast quantities of young Oysters are conveyed by the fishermen, and suffered to increase without 

 molestation. Newly formed beds'are untouched for two or three years. During the months of May, June, 

 and July, the Oysters breed, and are considered unfit for food. At this time the young, called spat, are 

 deposited in enormous numbers. They instantly adhere to the substance among which they fall, and this, 

 whatever it be, is called cultch, and is' protected by severe penalties. About May, the fishermen separate 

 the spawn from the cultch. which is then thrown back into its former place. After May, it is felony to 

 disturb the cultch, as were it removed, muscles and cockles would rapidly take the place of the Oysters. 

 The Oysters are taken in the proper season by the dredge, a kind of small net, fastened round an iron frame- 

 work, which scoops up the Oysters, and many other marine animals. The part of the Oyster called the 

 beard, is in reality the respiratory apparatus. 



Dredging for Oysters is necessarily prosecuted in fleets, as the beds lie within a comparatively small 

 compass. Each boat usually carries two men, or a man and a boy, and is about fifteen feet long, 

 dredge is of about eighteen pounds weight! Each boat is provided with two dredges. 



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The 



