MONOGRAPH OF THE EXISTING CRINOIDS. 743 



Comissia scitulus. Dorometra mauritiana. 



Comaster serrata. Dorometra nana (most individuals). 



Comanthus annulata (many). Leptometra celtica. 



C atoptometra opJiiwa (most). Leptometra phalcmgium. 



Lamprometra prote.ctus (many). Hathrometra tenella. 



Omitting these sporadic green species, we find yellow, deepening to brown, 

 more rarely tending toward orange, often associated with white or nearly white 

 cirri, to be characteristic of the following groups : 



Antillean Capillasterinae. lleliometrinse (except individuals of two 



Thalassometrinse (with few exceptions). .species). 

 Charitometridse. Bathymetrinse. 



Thysanometrinae. Pentametrocrinidse. 



Red. deepening to purple and brown, is characteristic of the following group : 



Comactiniinse. 



Purple or purplish brown, with white cirri, is, except for the genus Lepto- 

 metra, characteristic of the Zenometrinae. 



Mixed (either in the individual or in the species) yellow, red, purple, violet, 

 white, and brown are characteristic of the following : 



Zygometra. Ptilometrinae. 



Tropiometridse. Pcrometrinse. 



Red (deepening to purple) and yellow (deepening to orange), with brown, 

 gray, and white, are characteristic of 



Antedon. 



Red and yellow characterize most of the specimens of the species of 



C atoptometra. 



Purple, white, brown, yellow, green, and black characterize, except for the 

 genus Antedon, the 



Antedoninee. 



Purple and yellow, deepening to orange and red. 



Stephanomtridse. 



White, gray, yellow, orange, brown, and purple. 



Calometridae, Homalometra. 



Eight or nine colors in all conceivable combinations : 



Capilla&terinae (except West Indian). Himerometridae. 



Comasterimv. Mariametridae. 



Colobometridse (except West Indian). 



Whereas the, development of color in the crinoicls seems to have a more or less 

 definite relation to illumination, it appears to have no relation whatever to the 

 temperature of the water in which the crinoids live. 



From the warm water of the tropical littoral the various colors range down- 

 ward, as follows : 



Yellow to 28.7 F. White to 37.5 F. Red to 40.6 F. Gray to 43.3 F. 

 Violet to 28.7 F. Black to 37.5 F. Orange to 40.6 F. 

 Brown to 32.8 F. Green to 40.3 F. Purple to 43.0 F. 



142140 21 Bull. 82 49 



