THE PAPER NAUTILUS, 



Pearl muscle Description. 



The pearl muscle has a flattened and nearly 

 orbicular shell, about eight inches long, and 

 somewhat more in breadth. The color of the 

 exterior is very various, being in some indivi- 

 duals sea-green, in others chesnut, or even bloom, 

 color, with white rays, and sometimes whitish 

 with green rays. The young shells resemble 

 scallops, having ears as long as the shell. The 

 pearl is a calculus, or morbid concretion, which 

 is produced no-t only in this, but sometimes even 

 in the common oysters and muscles ; but in these 

 it is generally very small, and of little value. 

 It is found both in the body of the animal and 

 in the shells on the outside of the body. For 

 particulars relative to the fishery for pearls, see 

 our account of Oysters. 



THE PAPER NAUTILUS, or ARGO- 

 NAUT. 



THIS species, which is six or eight inches in 

 length, and but little either thicker or stronger 

 than paper, is found in the Mediterranean sea, 

 and in the Indian ocean. It is the famous nau- 

 tilus of the ancients, and is supposed, in the 

 early ages of society, to have furnished the ori- 

 ginal idea of navigation. When it means to 

 sail, it discharges a quantity of water from its 

 shell, by which it is rendered lighter than the 

 surrounding medium, and of course rises to the 



