JEAN LOUIS RODOLPHE AGASSIZ. 479 



Agassiz found to be peculiar to the fossil fishes of the earlier 

 geologic ages. There is no trace of a vetebra, but the apophy- 

 ses, usually ossified, rest directly on the spinal cord. 



In October, 1833, Agassiz married Cecile, the sister of. his 

 life-long friend Alexander Braun. With rare artistic talent she 

 had greatly aided her brother by making drawings of botanic- 

 al objects, and she now performed a similar service for her 

 husband. 



The appearance of the first part of his Fossil Fishes had 

 won for Agassiz the Wollaston prize of the Geological Society 

 of London. In 1834, and again in 1835, Agassiz visited Eng- 

 land and received the kindest attentions from Buckland, Sedg- 

 wick, Murchison, Lyell, and others, and much aid in his re- 

 searches. 



Agassiz next turned his attention to the study of Mollusca 

 and Echinoderms, and in 1836 published a prodromus of the 

 Echinoderms, and in 1837 a treatise on the fossil Echinoderms 

 of Switzerland. In 1839 he began a more elaborate work, en- 

 titled Monographic* Echinodermes vivants et fossiles, a most 

 important contribution to modern zoology. This work com- 

 prises five parts : the first and second, on the Salenies and 

 Scutella, by Agassiz ; the third and fourth, on the Galerites 

 and Dysaster, by Desor ; and the fifth, Anatomic du genre Echi- 

 nus, by Valentin. While he was publishing his work on the 

 Echinoderms, this indefatigable naturalist also described and 

 figured a large collection of fossil shells from the Oolite and 

 Cretaceous formations, in a work entitled Etudes critiques sur 

 les Mollusques du Jura et de la Craie, besides issuing an anno- 

 tated German translation of Bucklarid's Geology, and French 

 and German translations of Sowerby's Mineral Conchology. 



Notwithstanding the immense amount of work on his hands, 

 Agassiz found time to prosecute his investigation upon the 

 fresh-water fishes of Europe. The first part of his work upon 

 them, issued in 1839, is devoted to the genera Salmo and Thy- 

 mallus. The second part, which did not appear till 1842, con- 

 sists of a folio of plates and a volume of text on the Embry- 

 ology of the Salmons, by Carl Vogt, whom Agassiz had associ- 

 ated with him in his work. This excellent treatise was never 

 completed; Agassiz's departure for the United States shortly 

 after, and his increasing responsibilities, prevented the perfect- 

 ing of his original plan. 



