Preface 



THE SYSTEMATIST has divided the Superclass Pisces into two major groups: 

 the elasmobranchs with an internal supporting skeleton of cartilage only, and bony 

 fishes with a skeleton consisting of true bone in greater or lesser amount, or some deri- 

 vation of it. Parts i and 2 of this series have already treated the sharks, skates, and rays, 

 which comprise the elasmobranchs. With publication of Parts 3—5, this series enters the 

 realm of bony fishes, by far the larger and more diverse of the two groups. The fishes 

 treated here, commonly referred to as "soft-rayed bony fishes," include the anadromous 

 sturgeons and gars, the wide-ranging and numerous groups of herring-like isospondylids, 

 the little-known giganturoids, the broad assemblage of iniomes, and finally the strange- 

 looking lyomerids. The Introduction and Table of Contents for each volume provide 

 detailed information as to the subjects treated by the various authors. 



The diverse shapes and characters of the forms detailed in these volumes, well 

 known to the ichthyologist and many students of oceanography, constitute a notable 

 display of the devious developments and modifications that have occurred in the course 

 of evolutionary changes throughout time. This is also quite apparent to the average 

 reader from a mere glance at the illustrations. Certainly none among nature's multi- 

 plicity of creatures is more bizarre than the oddly shaped hatchet fish with its tubular 

 eyes and luminous organs, or the pelican fish with its long eel-like body and an enormous 

 mouth that allows it the unusual ability to devour prey larger than itself. Indeed, so 

 unusual and diverse are many of the groups treated here that even the trained system- 

 atist is put to it even to approximate their correct position on the ichthyological tree. 

 Parallel with their diverse development in form, we also find pronounced modifications 

 in their mode of life and habitat, as in the anadromous sturgeons and gars who have 

 assumed the capacity to live in both fresh and salt water, and the deep-sea creatures 

 who have adjusted to life at great depths under tremendous pressure where no sunlight 

 penetrates. 



In Parts 3—5, as in the two previous volumes, our objectives have remained the 

 same — to provide for both professional and nonprofessional readers "critical reviews and 

 revisions of each group rather than perfunctory compilations or mere reprintings of 

 previously published works." The extent to which these objectives are fulfilled in each 

 section will be determined by the usefulness of the account to both groups of readers. 



