740 



BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



This would seem to indicate that all colors except gray and black may arise 

 directly from white; and that yellow, red, and brown usually arise directly from 

 white, while violet arises as often from white as from any other color. 



All colors may develop ( ?secondarily through white) from yellow; gray and 

 black arise only from yellow; and purple and green arise more frequently from 

 yellow than from any other color. 



Red frequently develops ( ?from white through yellow) into purple, and occa- 

 sionally into yellow, violet, and green. 



Brown develops into green and, less frequently, into violet. 

 Orange develops into brown. 



It is worthy of mention that in Catoptometra rubroflava the cirri are 

 orange a color intermediate between the bright red and bright yellow of the arm 

 bands. 



The relative frequency of the different colors is shown in the following table : 

 Yellow occurs In a total of 88 species ; alone in 45 ; combined in 43. 



alone in 0; 

 alone in 24; 

 alone in 10; 

 alone in 8 ; 

 alone in 

 alone in 

 alone in 

 alone in 

 alone in 



At a depth of 55 fathoms in the sea the relative proportion of the red rays 

 is considerably diminished, and at 300 fathoms they have almost completely dis- 

 appeared. In a discussion of colors, color combinations, and color types and their 

 relation to depth, therefore, it would seem that bathymetric divisions of 0-55 

 fathoms, 55-300 fathoms, 300-600 fathoms, and 600 fathoms and over would be 

 as satisfactory as any. 



The bathymetrical distribution of the colors and color types is made clear in 

 the following table : 



White occurs in a total of 37 species ; 

 Brown occurs in a total of 36 specios; 

 Purple occurs in a total of 34 species; 

 Red occurs in a total of 20 species; 

 Violet occurs in a total of 19 species; 

 Green occurs in a total of 17 species ; 

 Ornnge occurs in a total of 13 species; 

 Black occurs in a total of 8 species; 

 Gray occurs iu a total of 7 species; 



combined in 37. 



combined in 12. 



combined in 24. 



combined in 21. 

 6 ; combined in 13. 

 7; combined in 10. 

 5; combined in 8. 

 3 ; combined in 5. 

 1; combined in (5. 



