Whalebone- 
whales (Saleno- 
dea).—In the em- 
bryo whales of this 
group minute teeth 
are present. They 
are absorbed before 
birth, and after it 
their place is taken 
by baleen, or plates 
of whalebone, that 
grow out and hang 
down upon each side 
in from three to four 
hundred plates, like 
saws on arack, often 
attaining a length of 
ten feet, weighing 
in all one ton (Fig. 
336). The outer 
edges are smooth, 
the inner frayed into 
numerous bristles, 
that form a rude 
strainer. Ordinari- 
ly, the lips of the 
lower jaw cover 
them, but, when 
feeding, the enor- 
mous lips flatten 
out, presenting the 
appearance of a 
scoop with whale- 
bone sides. Into 
MAMMALIA, 
Ww 
_= 
Land 
Ja, fore-arm; 4, hand; , th, 7, small remains of pelvis or hip-bone, thigh, and leg; 7, roof of the palate; 
Fic. 336.—Skeleton of a whalebone-whale, and section of the mouth, with whalebone : 4, blow-hole; a, upper arm; 
w, w, plates of whalebone ; /, whalebone-fiinge. 
this trap myriads of jelly-fishes are swept, becoming en- 
tangled in the strainer; when a mouthful is obtained, the 
