248 LOUIS AGASSIZ. 



laboratories, giviug- to tbe names of liis collaborators a secondary place. 

 It was be wbo inspired tbe work, wbo collected tbe material, wbo bore 

 tbe expense of tbe pnblication. But tbe aids soon demanded tbe credit 

 tbey considered tbeir due; bence arose dissatisfaction and disagreements, 

 wbicb continued to increase until tbe union was dissolved. Mr. Vogt 

 was tbe first to leave tbe association in order to g;o to Paris ; Mr. Desor 

 continued to labor on Agassiz's works, even after tbe departure of tbe 

 latter for America. He later joined tbe savant tbere, but be afterward 

 returned to Europe. One cannot but regret tbat tbese personal ques- 

 tions sbould bave interfered so soon witb tbe bappy scientific labor of 

 tbat time. 



Agassiz passed tbe muter of 1845-'4G at Paris. Tbe vast collections, 

 public and private, of tbat city were generously placed at bis disposal, 

 and enabled bim to complete, witb tbe valuable assistance of M. Desor, 

 bis researcbes upon tbe Ecbinoderms. Tbose of Alcide d'Jrbigny, 

 of Desbayes, of Mecbelin, of Graves, of Alexander Bronguiart, of de 

 Verneuil Avere in turn examined. Tbe gallery of tbe museum con- 

 taining tbe Ecbinoidea was reserved for bim and closed to tbe public, 

 and bitber were brougbt in succession all tbe cases and barrels contain- 

 ing Ecbinoids. Considerable material, derived from tbe scientific ex- 

 plorations of Baudin, of Freycinet, of Captain Duperre, passed also 

 tbrougb bis bands. All tbese documents were used in tbe publica- 

 tion of tbe Catalogue raisonne. According to tbe classification adopted, 

 tbe Ecbinoderms are subdivided into tbree orders: Tbe Stelleroids 

 wbicb include tbe Asteroids, tbe Opbiuroids and tbe Crinoids, ra- 

 diated animals, eitber free or fixed, and of wbicb tbe body is furnisbed 

 witb rays. Tbe Ecbinoids, or sea-urcbins, witb a body globular and 

 covered witb regular plates, and tbe Holotburioids, of wbicb tbe body 

 is coreaceous, or leatberv, and elongated. He divided tbe Ecbinoids 

 into foiu- families: Cidarida, Clypeastroidea, Cassidulidea, and Spatau- 

 goida. In bis preceding works be deduced from tbe structure of tbese 

 animals and tbeir successive appearance important consequences for tbe 

 general bistory of creation. 



He sougbt at tbe same time to propagate tbe glacial tbeory, wbicb 

 still encountered in tbe ranks of Freucb science a lively opposition ; 

 but be discussed it only in private conv^ersation. Tbis subject did not 

 excite mucb interest in tbe scientific public, wbo knew little of tbe 

 mountains, and tbe beads of science entertained contrary ideas. 



Tbis same year Agassiz, wbose reputation was already far extended, 

 was called to Boston, in America, by Mr. Lowell, director of tbe Lowell 

 Institute, to give some lectures. He was also, tbanks to Humboldt, 

 cbarged by tbe King of Prussia witb a scientific commission in tbat 

 country. He went to England in tbe summer of 1846, and sailed for 

 Boston in tbe montb of September. 



