744 BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



The various color types are almost entirely confined to water of high or inter- 

 mediate temperature. But this is undoubtedly due to the fact that the crinoids 

 of the colder parts of the oceans belong to groups in which color patterns are not 

 developed even in their tropical representatives. 



This supposition is emphasized by the occurrence of several well-marked and 

 beautiful colors types in the species of the genus Antedon, which are quite as well 

 developed in the Scandinavian species as in those inhabiting the shores of north- 

 western Africa and the Mediterranean. 



Antedon belongs to the subfamily Antedoninje, which otherwise is confined to 

 the Indo-Pacific region; and in its migration to the Atlantic basin it appears to 

 have retained undiminished the group character of diversified coloration. 



Geographically the maximum development of color diversity appears to be in 

 the Malayan and north Australian region, and thence westward to Ceylon; but 

 it is here also that the maximum development of littoral types is found. The whole 

 littoral and intermediate fauna from east Africa to Oceania and southern Japan is 

 notable for the diversity in the coloration of the endemic forms. 



On the other hand, throughout the vast extent of the east and north Pacific 

 we find the minimum diversity of crinoid coloration ; all of the comatulids are uni- 

 color, most of them yellow, becoming yellow brown, a few purplish brown : all of 

 the stalked forms are yellow. 



The crinoids of the Caribbean Sea, as known to-day, are much less highly 

 colored than those of the Indo-Pacific region, and this holds good for stalked 

 as well as for unstalked types. But here the groups which furnish the majority 

 of the most variegated species, both of the littoral and of the intermediate fauna, 

 in the Indo-Pacific, the Comasterinae, Zygometridae, Himerometridse, Stephano- 

 metridae, Mariametridee, Colobometridse (except for the genus Analeidometra) . 

 Calometrida?, Ptilometrime, and Antedoninse (except for a single species of A/it, - 

 don) are absent. The only littoral types are Antedon dubcnii, Tropiometra picta, 

 which has a rather limited range and a fairly constant scheme of coloration, species 

 of Nema#ter which, so far as we know, are always uniform brown, and species 

 of Comactinia which, as in the case of its eastern representatives, are practically 

 unicolor. 



In the remaining portions of the Atlantic (outside of the region of the Cape 

 of Good Hope, where the Indo-Pacific fauna intrudes for a short distance) we 

 note especially the presence of the highly colored species of Antedon, which range 

 collectively from Kio de .Janeiro to St. Thomas and from the Gulf of Guinea to 

 Norway, including the Mediterranean basin; of the green species of Leptometra, 

 which range from Madeira to Scotland, including the Mediterranean basin; and 

 the small green or gray species of Il<illirnii-lr<i. which range from Chesapeake 

 Hay and Portugal northward. 



The coloring matter of crinoids is freely soluble in fresh water and in alcohol. 

 It is possible to keep certain species for some time in water fresh enough to dis- 

 solve out a considerable amount of pigment without apparent injury, while many 

 can be partially decolori/.ed in a stream of fresh water while still alive. 



