332 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



the young of Comatula carinata Lamarck. In a paper published in December 1908, 

 I discussed the coloration of this species, describing it as a mosaic with both a yellow 

 and a red base. 



Prof. F. Jeffrey Bell hi 1909 recorded Antedon carinata from Saya de Malha in 

 300-500 fathoms ; north reef, Farquhar atoll; Cargados Carajos in 30 fathoms; and the 

 Seychelles in 15 fathoms. The specimens had been collected by the Percy Sladen 

 Trust expedition in the Sea Lark under the direction of Prof. J. Stanley Gardiner. 

 The record from Saya de Malha probably refers to some other species, as Tropiometra 

 carinata in the Indian Ocean seems to be a strictly littoral form. 



In a paper on the crinoids of the Copenhagen Museum published in 1909, under 

 the heading Tropiometra carinata I said that specimens from South Africa, east 

 Africa, the East Indies, and the south Pacific ocean are very uniform in their char- 

 acters, and agree in having a moderate or slight carination of the brachials; on the 

 coast of Brazil and in the West Indies the brachial carination is as a rule much stronger, 

 and may be extravagantly developed and correlated with spinous distal ends to the 

 pinnule and cirrus segments; but on the other hand specimens may readily be found 

 quite as smooth as any from the Indian Ocean. This enormous range in the extent 

 of carination is accompanied by meristic variation, for 6-rayed specimens are not at 

 all unusual hi Brazil. As a species introduced into a new locality, provided it sur- 

 vives, becomes as a rule much more variable than in its native habitat, it might well 

 be argued that Tropiometra carinata is a comparatively new element in the west-central 

 Atlantic fauna, not yet old enough to have, through elimination of the economically 

 unfit, attained a definite varietal form, the more strongly since the only other species 

 of the genus, and all the remaining genera of the family [as considered at that time] 

 are restricted to the seas lying between northern Australia and southern Japan. 

 I added that one feature of the distribution of this species is of considerably more 

 than ordinary interest. In the Lesser Antilles it occurs between 200 and 300 fathoms 

 instead of littorally and sublittorally, as throughout the remaining portions of its 

 range. A similar phenomenon at Rockall has been taken as indicating that that 

 ocean landmark has sunk within comparatively recent times, carrying down its 

 echinoderm fauna with it. But the case in the West Indies is susceptible of a more 

 satisfactory explanation. The Amazon and Orinoco Rivers interpose an insuperable 

 barrier, insofar as the littoral crinoids are concerned, between the Brazilian coast 

 and the Antilles. But an adaptable species, provided there were a suitable food 

 supply, could surmount this barrier by the simple process of gradually increasing the 

 depth of its habitat and thus passing under it, ir water of a sufficient depth to insure a 

 uniform salinity. Thus it is possible that Tropiometra carinata has extended its 

 range northward from Brazil by passing under the fresh water discharged into the 

 sea by the Amazon and Orinoco, and, having reached the Antilles, has not yet risen 

 again to its normal littoral habitat. A species of Comasteridae, Nemaster lineata 

 ( = JV". rubiginosa), the only other littoral comatulid found in Brazil, agrees with 

 Tropiometra carinata in inhabiting deep water in the West Indies. In the same 

 paper I recorded and gave notes upon a very fine specimen of Tropiometra carinata 

 from Zanzibar. Under the same name I included a specimen from the East Indies 

 (encrinus) . 



In a paper on the recent crinoids of the coasts of Africa published in 1911, I 



