XI BLOWHOLE AND SPOUTING 345 
to be seen on the throat. 
This is especially the case with the 
Rorquals, in which group the Humpback Whale, Megaptera, is 
to be included. The whales of 
these two genera (Balaenoptera 
and Megaptera) have a large num- 
ber of the throat furrows—as 
many as sixty have been counted. 
Some other Whales have a smaller 
number; thus Rhachianectes has 
but two on each side, and the 
Physeteridae have not many more. 
These furrows are absent in very 
young embryos. It is thought 
by Professor Kiikenthal that they 
allow of a wide opening of the 
mouth. 
The blow-hole of Whales is, of 
course, the aperture of the nostrils, 
which are not so far back in the 
foetus as in the adult. By the 
characters of the nostrils the 
Toothed Whales can be distin- 
guished from the Baleen Whales ; 
in the latter the orifice is double, 
in the former single. In embryos 
of Dolphins, however, the two aper- 
tures are quite independent. The 
phenomena of spouting have often 
been misinterpreted.t When the 
Whale breathes, the expired air 
rushes out through the nostrils. 
The water vapour in the breath 
condenses into drops of water in 
the cold Arctic regions where 
the phenomenon has been mainly 
observed. 
expelled through the blow-hole. 
Fic. 181.—Dorsal surface of bones of 
right anterior limb of Round-headed 
Dolphin (Globicephalus melas). x 3. 
The shaded portions of the digits 
are cartilaginous. c, Cuneiform ; H, 
humerus; Z, lunar; &, radius; s, 
scaphoid ; ¢d, trapezoid or magnum ; 
U, ulna; u, unciform ; ZJ-V, digits. 
(From Flower’s Osteology.) 
Hence the idea that water taken in at the mouth is 
As the Whale approaches the 
surface to breathe, it may be that some of the water of the sea is 
1 «And at his gills draws in, and at his trunk spouts out, a sea,’ wrote Milton, 
and think many others. 
