53n 



THE AMERICAN NATURALIST [Vol. XLIX 



where except in inland seas, asymmetry is especially 

 developed in the warm waters of the eastern tropics, par- 

 ticularly in the Malayan region and in northern Australia, 

 and in the Antarctic and the cold abysses. 



Bathymeteical Distribution of the Asymmetrical 

 Crinoids 



The number of genera of recent crinoids including 

 asymmetrical species, the number of genera including 











500-550 

 550-600 



650-700 

 700-750 

 750-800 

 800-850 

 850-900 



950-1,000 

 l!20(tl!.300 



lisoo-ilooo 



1,900-2,000 

 2,000-2,500 



2 



39 

 34 



13!2 



2L0 

 25.0 

 25.0 

 33.3 



ber of symmetrical genera represented by the number of 

 asymmetrical genera at different depths are given in the 

 table on page 528 and shown in Fig. 1. 



Considering the percentages only, these may be re- 

 grouped as follows : 



