from 40 to
100 fine ventral grooves, longest extending at least to navel;
head lacks knobs Go to 6

6. a. Three ridges on head, one from blowholes, forward towards tip
of snout, one auxiliary groove along each side of main ridge;
40-50 ventral grooves; 250-300 slate-gray baleen plates with
15-35 dirty gray bristles per centimeter.
Bryde's whale, p. 37

b. Only one prominent ridge on head,[19] from just in front of
blowholes forward towards tip of snout; 55-100 ventral grooves
Go to 7

7. a. Head broad and U-shaped; dorsal fin less than 13 inches (33 cm)
and very far back on tail stock; baleen all black with 10-30
black bristles per centimeter; plates extremely broad relative to
length.
Blue whale, p. 19

b. Head broad at gape but sharply pointed on tip; dorsal fin to
24 inches (61 cm) and slightly more than one-third forward from
tail; right front one-fifth to one-third of baleen ivory white to
yellowish white, remainder dark gray to bluish gray streaked with
yellowish white; plates have 10-35 gray or white bristles per
centimeter and are narrow relative to length.
Fin whale, p. 26

8. a. Top of snout not covered with callosities; 325-360 baleen
plates per side, longest reaching 14 feet (4.3 m); plates black
with black bristles (anterior portion of some plates may be
whitish).
Bowhead whale, p. 49

b. Top of snout covered with callosities, often including lice
and/or barnacles; 250-390 baleen plates per side, longest
reaching 7.2 feet (2.2 m); plates dirty or yellowish gray (some
anterior plates all or part white and some posterior plates brown
or black) with 35-70 bristles per centimeter.
Right whale, p. 52

9. a. Upper part of head extending appreciably past tip of lower jaw;
lower jaw markedly undershot and considerably narrower than upper
jaw Go to 10

b. Upper part of head not extending appreciably past tip of lower
jaw; lower jaw approximately same width as upper jaw Go t