740 



BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



This would seem to indicate tliat 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 a,s 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. 



Eed 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 ruhro-jiava 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 speeios ; alone in 45 ; combined in 43. 

 White occurs in a total of 37 species; alone in 0; combined in 37. 

 Brown occurs in a total of 36 speeios; alone in 24; combined in 12. 

 Purple occurs in a total of 34 species; alone in 10; combined in 24. 

 Red occurs in a total of 20 species ; alone in 8 ; combined in 21. 

 Violet occurs in a total of 19 species; alone in 6; combined in 13. 

 Green occurs in a total of 17 species; alone in 7; combined in 10. 

 Orange occurs in a total of 13 species; alone in 5; combined in S. 

 Black occurs in a total of 8 species; alone in 3; combined in 5. 

 Gray occurs in a total of 7 species; alone in 1; combined in 6. 

 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: 



