x INTRODUCTION. 



To Mr. Cotteau the Cambridge Museum is indebted for a fine series of 

 the many new genera and species described by him in the Echinides de 

 la Sarthe, in the Paleontologie franeaise and other papers. In his private 

 collection at Auxerre were also authentic specimens of many of the 

 species described by Desor and Michelin ; the recent species it contains 

 have been in many cases labelled by both Michelin and Desor. 



Another most important collection, containing much of the material 

 of the Catalogue Raisonne, is the collection of Deshaves and that of 

 Michelin, now in the Ecole des Mines. Michelin described a large num- 

 ber of species, which are here carefully labelled in his own handwriting, 

 making it possible to identify all the species described by him in the 

 Revue et Magazin de Zoologie, thanks to the courtesy of Professor Bayle. 



At Vienna, I saw the collections of the Novarra Expedition made by 

 Frauenfeld. 



The only collection of importance which 1 have not personally exam- 

 ined is that of Desmoulins, owing to the breaking out of the Prusso-French 

 war. The greater part, however, of his species are in the collections of 

 the Cambridge Museum, having once formed a part of the collection 

 brought to this country by Professor Agassi/,, with whom he was in cor- 

 respondence during the working up of the Catalogue Raisonne. 



To Mr. Bouvier I am indebted for a most interesting collection from 

 Cape de Verde Islands. To Mr. Crosse for a number of species from 

 New Caledonia, and to all the gentlemen named above for typical speci- 

 mens carefully compared with the originals of all the species which could 

 be spared. 1 have thus succeeded in bringing together in Cambridge, with 

 the addition of the information obtained by comparisons with specimens 

 sent from Cambridge for that purpose, an unrivalled historical collection, 

 for which I cannot thank too cordially the many friends in Europe who 

 have so generously assisted me in my labors. 



The materials existing in the United States have in a similar way 

 been carefully examined. The whole of the collection of Echini of the 

 Smithsonian Institution has, thanks to the generosity of Professors Henry 

 and Baird, been in my hands for a considerable period. It contains 

 the materials of the several explorations of the east and west coast 

 of the United States, made under the direction of the Smithsonian. To 

 Dr. Stimpson I owe the opportunity of studying the Echini of the 

 North Pacific Exploring Expedition, collected by himself. The Academy 



