CHAPTER X 



TOPS AND TURBANS 



We now come to a great group of shells quite 

 unlike any that we have previously considered. In 

 the first place the shells of nearly all of these mol- 

 lusks are lined with a more or less iridescent mother- 

 of-pearl. In some species the prevailing color of it 

 is green and in others it is red, while in a few the 

 shell is nearly white; but in any case if you turn 

 the shell in the sunlight you will get glimpses of 

 rainbows with their varying tints, sometimes feeble 

 but never absent. In most cases this feature of the 

 inner shell remains not only long after the death of 

 the animal, but long after the shell itself has crum- 

 bled into scales and fragments, through exposure to 

 the weather. 



The ordinary colors of shells are usually quite 

 permanent but they differ materially in certain re- 

 spects. Some colors are found only on the surface of 

 the shell, or at most they penetrate but a very little 

 distance. Others go down deep and seem to be made 

 by a mixing of the dye with the substance of the 

 shell, as it is moulded by the mollusk artist. A good 

 example of this is seen in the Purple-hinged Pecten, 

 which has been described on a previous page, in 

 which the rich color remains in the little fragments 

 of the shell that may be found among the sands of 

 the beach. 



