Vol. 51.] ANNIVERSARY ADDRESS OF THE PRESIDENT. li 



in 1828, and was trained for the law. But he early took a keen 

 interest in the Natural History of the Department of the Yonne, 

 with which he was always associated. At the age of 19 he published 

 his first papers on science ; these were a sketch of the geology of the 

 department, and a short paper on the glaciation and erratics of 

 Chatel-Censoir, a locality which he subsequently made famous by 

 the description of its echinoid fauna. He began work as a general 

 geologist and palaeontologist, writing papers on Jurassic stratigraphy, 

 on fossil mollusca and fish (on Ptycholejpisva. 1865), on caves (1859), 

 and even on recent mollusca (1854). At the age of 21 he had, how- 

 ever, begun a monograph on the fossil Echinoids of the Department 

 of the Yonne, a work which was not concluded till 27 years later. 

 He soon became especially interested in this group, and after the 

 death of his illustrious friend, E. Desor, was recognized as the fore- 

 most of descriptive systematic echinologists. His principal works 

 were his series of monographs on the Echinoidea of the depart- 

 ments of the Yonne (1849-1876), the Aube (1865), and the Sarthe 

 (1855-1869), the last of which was written in conjunction with 

 Jules Triger ; on those of Algeria (1876-1885), a work shared 

 by MM. Peron and Gauthier ; the two series of memoirs entitled 

 ' Echinides nouveaux ou peu connus ' (1858-1893) ; and, finally, his 

 description of the Echinoidea of the Jurassic, Cretaceous, and 

 Eocene systems in France. The last was issued in the 'Paleonto- 

 logie Frangaise,' in continuation of the work begun by Alcide 

 d'Orbigny ; it occupied six volumes of text, and is illustrated by an 

 atlas of over 1100 plates. But, in addition to these, he wrote over 

 100 shorter contributions. Most of these dealt with small faunas 

 of Echinoidea, or with species of especial interest from their structure 

 or distribution. Echinoids from all parts of the world were sent 

 to him for description. The most interesting faunas came from 

 Australia, Mexico, Cuba, St. Bartholomew, and Anguilla (1875 and 

 1877), Syria, India, Belgium, and Spain. The two most remarkable 

 genera that he described were probably Asterostoma and Tetracidaris, 

 the latter of which is the only post-Palaeozoic echinoid known that 

 has more than two rows of plates in each interradius. 



Cotteau's work was characterized by most scrupulous care in 

 describing new species ; he gave lengthy descriptions of his speci- 

 mens rather than succinct diagnoses, but these are models of detailed 

 examination and accurate description. 



Some of the younger palaeontologists were inclined to think that 

 ho attached exaggerated value to minute differences and variations, 

 but in the description of specimens from foreign localities this is an 



