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THE AMERICAN NATURALIST [Vol. XLII 



There appears to be no direct relation between the 

 color of crinoids and their environment. The yellow 

 deep water species are very conspicuous in the mud from 

 a deep dredge haul, while the color of shallow water 

 species, as just indicated, is commonly in great contrast 

 to their surroundings. Crinoids can have little to fear, 

 because their extremely calcareous organization would 

 seem to make them very undesirable as food ; on the other 

 hand, a strongly contrasting coloration might be of ad- 

 vantage in attracting small organisms, as contrast spots 

 on flowers do insects; observations in this point would 

 not be difficult to make, and might lead to interesting 

 results. 



The other echinoderm classes appear to be in general 

 subject to the same laws of color change as the crinoids, 

 but the records are much more complete and satisfactory, 

 and the specimens are not so much changed in preserva- 

 tion. They would, therefore, offer an interesting field 

 for study. 



These are some of the more interesting inferences to be 

 deduced from an examination of the literature on the 

 Crinoidea in its present state; and, in view of the great 

 geological importance of the group, and its bearing on 

 important geologic problems, it is to be hoped that this 

 phase of the subject, as well as the systematic and 

 anatomical sides will in the future receive its due at- 

 tention. 



