this region without a dorsal fin. Each section is further divided
into those animals with a dorsal fin and those without. From that point,
animals likely to be confused in the field are grouped together and the
important differences between them are discussed.

The synoptic accounts of the species are followed by five appendices:
Appendix A discusses and illustrates man-made and applied tags and
natural markings on cetaceans and their importance in studies of natural
history. Appendix B discusses the data which are most important to
record in observations of cetaceans at sea, gives examples, and provides
blank sighting forms. Appendix C discusses possible causes of cetacean
strandings and the manner in which stranded animals should be handled
and adds a key and tables to aid in identifying stranded cetaceans.
Appendix D provides guidelines for collecting data on stranded cetaceans
and provides forms and specific instructions for taking standard
measurements. Appendix E lists institutions to be contacted in the event
of a cetacean stranding or for information.

A bibliography of useful references on cetaceans in general and
cetaceans of this region in particular and a directory to species
accounts are included.

[Illustration: Figure 5.--A humpback whale lying on its left side on the
deck of a Canadian whaling station. Note the fringes of baleen suspended
from the roof of the mouth. (_Photo by J. G. Mead_.)]

[Illustration: Figure 6.--Atlantic bottlenosed dolphin mother and calf
from northeastern Florida. Note the single open blowhole, a
characteristic that marks these animals as toothed whales. (_Photo
courtesy of Marineland of Florida._)]

[Illustration: Figure 7.--The open mouth of an Atlantic bottlenosed
dolphin from the northeastern Gulf of Mexico. All toothed whales have
teeth, which are used primarily for grasping rather than for chewing.
The number varies from 2 to over 250, though they are buried beneath the
gums in females and immature animals of several species, take peculiar
form in one (narwhal), and are extensively worn in others. (_Photo by D.
K. Caldwell._)]

HOW TO USE THE GUIDE

To Identify Animals at Sea

The three major sections of the guide (i.e., large, medium, and small
whales) are preceded by a directory to species accounts, which is a
summary of the most obvious characteristics of each species and in which
summary statements about each characteristic are arranged in parallel
order.