PALEONTOLOGY. 4! I 



assistance of C Vogt, Agassiz was enabled to elucidate many 

 obscure points in fossil fishes. Agassiz also introduced 

 emendations in the classification of recent fishes, and added 

 many new data regarding the evolution and the range in time 

 of the various families. His sub-division of fishes into 

 Placoidei, Ganoidei, Cycloidei, and Ctenoidei, according to 

 the scaly skeleton, was certainly one-sided and artificial, and 

 had to be discarded. At the same time, Agassiz conferred 

 a great boon when he brought the Ganoidei into the strong 

 relief of a sub-division, and insisted upon their importance 

 both as essential links in the phylogenetic history of fishes and 

 as a group comprising many specific types of high value for 

 the characterisation of geological horizons. Agassiz was the 

 first scientist who, in discussing the genealogy of fishes, 

 pointed out the correspondence between the characters of 

 different forms succeeding one another in time, and the 

 characters of successive phases passed through by an organism 

 during embryonic development. The observation was one of 

 those far-reaching truths which are now and then wrested from 

 nature; Haeckel worked out the same idea and elevated it 

 to its merited rank as a fundamental bio-genetic principle. 

 Hence, although the actual classificatory system proposed by 

 Agassiz for the fishes could not supersede the Cuvierian 

 system, and was soon appreciably changed for the better by 

 Johann Miiller's valuable works (1844), the name of Agassiz 

 will always be among the most honoured in ichthyological 

 literature. A later monograph on the remarkable fishes oj^he 

 Old Red Sandstone was in many respects supple mentaly to 

 the earlier work of the Neuchatel savant. 



A large number of special memoirs followed the works of 

 Agassiz and Miiller, and gave a greater insight into the remark- 

 able varieties and wide distribution of the remains of fossil 

 fishes. Those of Grey Egerton, Count Miinster, Andreas 

 Wagner (the Director of the Museum of Natural History in 

 Munich), Costa, Thiolliere, Pictet, Von der Marck, Kner, 

 Zigno, Steindachner, H. von Meyer, Traschel, are all works of 

 high palseontological merit. Pander's monographs on the 

 fossil fishes of the Silurian and Devonian deposits in 

 Russia (1856 and 1858) are distinguished by exceptional 

 discernment, and by the wonderfully successful drawings 

 of the microscopic structure of teeth and scales. It proved 

 a difficult matter to determine the essential characters of 



