Introduction 



PART 3 OF THIS Series deals with the more primitive groups of soft-rayed bony 

 fishes. The volume commences with a characterization of the class Osteichthyes (bony 

 fishes) and comparison of this group with the class Chondrichthyes (elasmobranchs), 

 followed by a characterization of the subclass Actinopterygii and a key to the various 

 orders dealt with here and in Parts 4 and 5 : Acipenseroidei, Lepisostei, Isospondyli, 

 Giganturoidei, Iniomi, and Lyomeri, all of which were originally to be included in this 

 volume. The characterization and discussion of the Isospondyli concludes with a short 

 key to the suborders and an extensive key to the external characters of all the families 

 of the orders noted above; this, then, also applies to Parts 4 and 5 as well as to this 

 volume. Because of the large number of groups in the Isospondyli, only part of the 

 families, mostly shallow-water, are included in this volume; the rest, mainly deep-sea, 

 are relegated to Part 4. Thus, in addition to the sturgeons and gars, this volume includes 

 accounts of the tarpon, ladyfish, bonefish, the numerous anchovies, the herring, men- 

 haden, shad, sardine, pilchard, gizzard shad, round herring, salmon, trout, and smelt. 



The geographic area covered extends from Hudson Bay southward to the Amazon 

 and seaward more or less to the mid-Atlantic, with Bermuda and the Caribbean areas 

 included. For the most part, only fishes living in brackish water or salt water have 

 been included. 



Unfortunately, the accounts of the Alepocephalidae and Searsiidae could not be 

 completed for inclusion in this volume. These are therefore represented by brief interim 

 accounts that contain enough information for general identification of specimens in this 

 category. 



In these volumes, museum and institutional names have been abbreviated ac- 

 cording to the following list: 



AM — Amsterdam Museum, Holland 



AMNH — American Museum of Natural History 



ANSP — Academy of Natural Sciences of Philadelphia 



BLBG — Biological Laboratory, U. S. Fish and Wildlife Service, Bureau 



of Commercial Fisheries, Brunswick, Georgia 



BMNH — British Museum (Natural History), London 



BNM — Bergens Museum, Norway 



