NO. IO PHYLOGENETIC STUDY OF RECENT CRINOIDS CLARK 67 



In the thermal distribution the more specialized components of the 

 character pairs exceed the more primitive in 26 cases, the reverse 

 being true in 1 1 cases. 



The excess in depth of the primitive characters over that of the 

 specialized is 1422 fathoms, each of the 18 primitive characters 

 having- an average depth of 196 fathoms, as against no fathoms 

 for each of the 19 specialized characters. 



The excess in temperature of the specialized characters over that 

 of the primitive is 141.9 , each of the 26 specialized characters having 

 an average temperature of 7.6 , as against 5.1 ° for each of the n 

 primitive characters. 



Thus it appears that, taken collectively, the specialized characters 

 are developed in shallower and warmer water than the more primitive. 



