158 



LIVING FOSSILS. 



( Antedori) ; although the latter, together with many other 

 subsequently discovered species, was a true crinoid. For 

 a long period these living crinoids were supposed to be of 



FIG. 54. A Living Pentacrinid. 



extreme rarity, only a few examples being from time to 

 time procured. With the development of deep-sea 



