INTRODUCTORY NOTE 



This present memoir is a continuation of a paper entitled, The 

 Genera of Fishes, from Linnceus to Cuvier, 1758-1833, seventy-five years, 

 with the accepted type of each, a contribution to the stability of scientific 

 nomenclature, published by the present writer in 1917. 



It is likewise a contribution to the stability of scientific nomencla- 

 ture. It covers what may be termed the mediaeval period of systematic 

 ichthyology, the time in which nomenclature is fairly established, but in 

 which, for want of a general zoological record, many papers have been 

 overlooked or forgotten. 



This period is especially marked by the studies of Professor Agassiz 

 on the fossil fishes, by the exhaustive record of the fishes of the East 

 Indies by Dr. Bleeker, and by the unification of ichthyological knowledge 

 by Valenciennes and by Dr. Gunther. Giinther's Catalogue of the Fishes 

 ■ of the British Museum, 1859-1870, must always remain the solid founda- 

 tion on which systematic zoology is built. This period is also marked by 

 the studies in comparative zoology by Dr. Johannes Miiller and by the 

 opening to science of the rich fresh-water fauna of North and South 

 America. In this period wrote also the keenest of taxonomic critics, Dr. 

 Gill, whose conceptions of genera and of families are likely in a large 

 degree to constitute the last word in regard to the status of groups of 

 this grade. Other notable writers whose work has been of a high order 

 are Richardson, Schlegel, Lowe, Egerton, Reinhardt, Poey, Heckel, 

 Kner, Pictet, Holbrook, Baird, Troschel, Owen, McClelland, Riippell, 

 Henle, Storer, DeKay, Ayres, Cooper, Girard and Cope. Of the many 

 writers in the period preceding the year 1870, Steindachner only, one of 

 the most industrious and accurate, is still living. When the writer vis- 

 ited him in Vienna in 1913 he was still, at the age of 79, hard at work, 

 and one important paper of his bearing date of 1915 has found its way 

 through the vicissitudes of censorship to my library. 



In accordance with the philosophy of evolution, the writers at the 

 end of this period have inverted the fish series, the simplest and most 

 ancient types being placed first in taxonomic records, rather than the 

 perch and its relatives, so long regarded as typifying the perfect or com- 

 pleted fish. 



