MONOGRAPH OF THE EXISTING CRINOIDS. 745 



The solution given off in alcohol is often quite different in color from the 

 animal itself. Thus the dark green Endoxocrinus wyvillethomsoni gives off a pink 

 color, and the golden brown Kemaster iowensia a dark green color. A further dis- 

 cussion of these phenomena will be given in the section dealing with the coloiing 

 matter. 



As a general rule comatulids preserved in alcohol, no matter what their original 

 colors may have been, become brown, usually a yellowish, more rarely a purplish, 

 reddish, or greenish brown, later slowly fading out to grayish white. The bands 

 and spots often persist for some time, though with entirely changed color values, 

 but they eventually disappear. 



The color transformation undergone by specimens in alcohol is sometimes 

 very striking. As instances I may mention that one of the most brilliant species 

 with which I am acquainted in life, C atoptometra rubroftava, banded bright red 

 and bright yellow, becomes a uniform reddish brown; the species of Antedon be- 

 come uniform yellowish brown; and a brown and yellow specimen of Amphimetra 

 discoidea became purplish brown and grayish white. 



On account of the wonderful diversity of the colors in life and of the alto- 

 gether extraordinary alteration of the colors by preservation, the greatest care is 

 necessary in identifying living specimens, especially from descriptions based on 

 preserved material, for the color may or may not be a good specific index; it usually 

 is not. Several supposed species have been based upon color differences which 

 would have remained undescribed had the specimens been allowed to fade before 

 determination. 



The color, and especially the color markings, of specimens in alcohol, which 

 may or may not bear a definite relationship to the living colors, are always worth 

 recording, for, strange as it may seem, they sometimes furnish an index of relation- 

 ship more reliable than any which may be deduced from the far more diversified 

 living colors. 



From the evidence at hand the following conclusions seem justified: 



1. White, which is the original color of the pentacrinoid young and occurs 

 frequently in the adults, denotes the more or less complete absence of pigment. 



2. (a) Yellow is the color of practically all of the more primitive forms, and 

 of many of the more specialized, throughout life, and with very few exceptions 

 (occurring in the brilliantly illuminated littoral), of small specimens and of 

 advanced pentacrinoids. 



(b) Orange or red, in reality an intensification of the yellow, is the color of a 

 few primitive forms, and of nearly all the young which are not yellow. 



3. After the full size has been reached a dusky factor makes its appearance 

 which may be generally diffused or more or less localized, and deepens, alters, or 

 obscures the original colors. 



Apparently a careful distinction must be made between tha greenish cast of 

 such types as Phri/nocrinu,t and Cal-amocrinus and the clear greenish yellow and 

 green of the shallow-water species, and the " dusky purple " of certain pentacrinites 

 and the brilliant purples and violets seen in littoral types. 



