Vocabulary Development
Key words are boldfaced and derivations of generic names of animals are given where they first appear in the text. In addition, derivations of many technical and zoological terms are provided in the text; in this way students gradually become familiarized with the more common roots that recur in many technical terms. An extensive glossary provides pronunciation, derivation, and definition of each term.

Chapter Prologues
A distinctive feature of this text is an opening essay placed in a panel at the beginning of each chapter. Each essay presents a theme or topic relating to the subject of the chapter. Some present biological, particularly evolutionary, principles; others illuminate distinguishing characteristics of the group treated in the chapter. Each is intended to present an important concept drawn from the chapter in an interesting manner that will facilitate learning by students, as well as engage their interest and pique their curiosity.

Chapter Notes
Chapter notes, which appear throughout the book, augment the text material and offer interesting sidelights without interrupting the narrative.

For Review
Each chapter ends with a concise summary, a list of review questions, and annotated selected references. The review questions enable students to test themselves for retention and understanding of the more important chapter material.

Art Program
The appearance and usefulness of this text are much enhanced by numerous full color paintings by William C. Ober and Claire W. Garrison. Bill's artistic skills, knowledge of biology, and experience gained from an earlier career as a practicing physician, have enriched the author's other zoology texts through several editions. Claire practiced pediatric and obstetric nursing before turning to scientific illustration as a full-time career. Texts illustrated by Bill and Claire have received Medical Illustrators, American Institute of Graphic Arts, Chicago Book Clinic, Printing Industries of America, and Book-builders West. Bill and Claire also are recipients of the Art Directors Award.

Web Pages
At the end of each survey chapter is a selection of related internet links dealing with the chapter's topics. The URLs for the pages are found in the text's Online Learning Center at www.mhhe.com/zoology (click on the book's cover).