66 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 65 



THE RELATION BETWEEN PHYLOGENETIC DEVELOPMENT 

 AND BATHYMETRICAL AND THERMAL DISTRIBUTION 



The relationship of phylogenetic development to depth and to 

 temperature presents a problem of considerable interest. 



In the following table is given the amount of excess of the more 

 primitive (1) or the more specialized (2) characters in each of the 

 thirty-seven contrasted pairs. 



In the temperature column the three figures marked with an 

 asterisk (*) represent the difference between two sharply marked 

 nodes in a single character pair. 



These double nodes all fall under the more primitive characters 

 ( 1 ) . The difference between each element of the three double nodes 

 and the average under the more specialized characters (2) are : 



In the bathymetric distribution the more primitive components of 

 the character pairs exceed the more specialized in 18 cases, while the 

 reverse is true in 19 cases. 



