Verrill, Notes on Radiata. 323 



JVb. 3. On the Geographiad Distribution of the Echinoderms of the 

 West Coast of America. 



Publisliod July, 1867. 



Althougli a large proportion of the Echinoclerms inhabiting this 

 coast were long since described, very little has been done toward the 

 study of tlieir distribution, and comparisons with the Echinoderm 

 Faunae of other regions. 



It is certain that our knowledge of the species inhabiting the vari- 

 ous districts upon this coast is still quite imperfect, for even the col- 

 lection of Mr. Bradley contains several undescribed species from 

 Panama, which was the region previously best known. But since the 

 collections which he has made, and those made by Mr. J. Xantus at 

 Cape St. Lucas, have contributed a large amount of new and authen- 

 tic materials for such investigations, it is thought proper to introduce 

 here a brief account of what is already known concerning this inter- 

 esting and important subject. 



The distribution of the species of the West Coast of America 

 should be studied with reference to several questions : — 



First. — To ascertain the range of each species along the coast, both 

 geographically and in the depth. 



Second. — To ascertain the extent and boundaries of the several 

 fauna?, which occupy the coast. 



Third. — To compare these faunoe with those of other regions, — espe- 

 cially the tropical fauna of the West Coast with that of the East 

 Coast and West Indies, and with that of the Pacific Islands and 

 East Indies. 



Fourth. — To compare the living species with those found fossil in 

 the Tertiary and more recent formations of the neighboring coasts, 

 and of the West Indies and Eastern North America. 



Very little material is now accessible for the investigation of the 

 subject included under the fourth head, but since prolific fossiliferous 

 deposits are known to occur near Aspinwall, as well as along the 

 western coast of South America,* many important results may be 

 expected when such localities shall have been fully investigated. 



The principal sources of information concerning the existing faunae 

 of the coast have, hitherto, been the works of Brandt' for the north- 



* A deposit abounding in fossils was examined by Mr. Bradley near Zorritos, Peru, 

 which is apparently of late Tertiary age, but the collection has not yet been ex- 

 amined with care. (See vol. ii, — Reprint). 



' Prodromus descriptionis animalium ab H. Mertensio in orbis terrarum circumuavi- 

 gatione observatorura. Recueil des Actes de la seance publique de I'academie imperiale 

 de St. Petersbourg, 1825. 



