The History of Ichthyology 405 



remarkable skill as a teacher made him the "best friend that 

 ever student had" and gave him a large following as a teacher. 

 Among his pupils in ichthyology were Charles Girard (1822- 

 1895), Frederick Ward Putnam, Alexander Agassiz, Samuel 

 Garman, Samuel H. Scudder, and the present writer. 



Johannes Miiller (1808-1858), of Berlin, was one of the 

 greatest of comparative anatomists. In his revision of Cuvier's 

 " System of Classification" he corrected many errors in group- 

 ing, and laid foundations which later writers have not altered 

 or removed. Especially important is his classical work, " Ueber 

 den Bau und die Grenzen der Ganoiden." In this he showed 

 some of the real fundamental characters of that group of ar- 

 chaic fishes, and took from it the most heterogeneous of the ele- 

 ments left in it by Agassiz. To Miiller we also owe the first 

 proper definition of the Leptocardii and the Cyclostomata, 

 and, in association with Dr. J. Henle, Miiller has given us one of 

 the best general accounts of the sharks (" Systematische Be- 

 schriebungen der Plagiostomen"). To Miiller we owe an acces- 

 sion of knowledge in regard to the duct of the air-bladder, and 

 the groups called Physostomi, Physoclysti, Dipneusti (Dipnoi), 

 Pharyngognathi, and Anacanthini were first defined by him. 



In his work oh Devonian fishes, the great British com- 

 parative anatomist, Thomas Henry Huxley, first distinguished 

 the group of Crossopterygians, and separated it from the gan- 

 oids and dipnoans. 



Theodore Nicholas Gill is the keenest interpreter of tax- 

 onomic facts yet known in the history of ichthyology. He 

 is the author of a vast number of papers, the first bearing date 

 of 1858, touching almost every group and almost every phase 

 of relation among fishes. His numerous suggestions as to 

 classification have been usually accepted in time by other 

 authors, and no one has had a clearer perception than he of 

 the necessity of orderly methods in nomenclature. Among 

 the orders first defined by Gill are the Eventognathi, Nema- 

 tognathi, Pediculati, Iniomi, Heteromi, Haplomi, Xenomi, and 

 the group called Teleocephali, originally framed to include all 

 the bony fishes except those which showed peculiar eccentricities 

 or modifications. Dr. Gill's greatest excellence has been shown 

 as a scientific critic. Incisive, candid, and friendly, there is 



