88 UINTACEINUS: ITS STEUCTURE AND RELATIONS. 



of Palseontologists — too frequently — to assume that fossils so occurring 

 were distinct. I have long been of the opinion that this has been too much 

 taken for granted, without facts to support the assumption. With regard 

 to the Crinoids, there are certain Upper Silurian forms in which I do not 

 believe it possible to separate the English and Swedish species from the 

 American, by any characters preserved in the fossil state, and the same 

 may perhaps be true of some Subcarboniferous forms. 



The best evidence on this point, however, is furnished by the living 

 Crinoids, of which there are a number of species, both stalked and un- 

 stalked, which have a geographical range fully as great as this would be, 

 and some of them greater. 



The following data as to the Geographical Distribution of Stalked 

 Crinoids and Comatulse in the present seas, taken from the works of 

 P. Herbert Carpenter,^ will afford instructive proof on this point : — 



Rhizocrinus lofotenns : Both sides of the Atlantic ; Lofoten Islands to Carib- 

 bean Sea, and South Atlantic, Lat. 35°, 89' S. 



RMzocrinus Rawsoni : Both sides of the Atlantic ; Azores to Caribbean Sea, 

 Yucatan Bank, and off Panama. 



Hyocrinus hethelianus : Mid Atlantic ; Southern Ocean ; East Pacific. 



Antedon tenella : Both sides of the Atlantic ; Coast of Portugal, Scandinavia, and 

 New England. 



Antedon carinafa : Both sides of the Atlantic ; St. Helena, Caribbean Sea, coast 

 of Brazil. Red Sea ; Indian Ocean ; Zanzibar ; Mauritius, Madagascar, and Cejlon ; 

 East Pacific ; Chih. 



Antedon quadrata^ A. Eschriehti, A. prolixa, and A. Duheni : All on both sides of 

 the Atlantic. 



Aetinometra pulcJiella : Both sides of the Atlantic ; off Rockfort, St. Paul's Rocks, 

 Bay of Biscay, Caribbean Sea. 



Aetinometra parvieurva : Both sides of the Pacific ; Borneo, Philippines, Japan, 

 Fiji Islands, Peru, Cape of Good Hope ; Ceylon. 



In order to afford those interested an opportunity to see the material 

 on which this paper is chiefly based, I have, in addition to the slab already 

 mentioned, presented to the Museum of Comparative Zoology the principal 

 type specimens figured on Plates II. to VII. inclusive. I have also placed 



* " Challenger " Rep. on Stalked Crinoids, pp. 386-7 ; Comatulae, pp. 200, 304, 373 et seq. Jour. 

 Linn. Soc., Vol. XXIV., p. 68. 



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