346 Dr. J. E. Gray on the Whalebone- Whales. 
specimen is short, and that it increases in size, and especially in 
length, much more rapidly than the rest of the body. This is 
very apparent in the Right or Greenland Whale, where the head 
of the adult is two-fifths, while that of the new-born is only 
two-sevenths, of the entire length of the animal. These differ- 
ences are shown by Eschricht in his figures. The head of the 
new-born and of the adult Cape Whalebone-Whale show the 
same difference ; but the head in both states is smaller, compared 
with the entire length of the animal, than in the northern or 
Greenland species. 
2. That the bones of the Whalebone-Whales in the very 
young state are the same in number, and nearly the same in 
form, as in the adult animal, the bones only becommg more or 
less completely ossified, which they appear to do very slowly, 
and in some species even more slowly than in others ; so that the 
notion that the number of vertebra increases with the growth 
of the animal, which has been entertained by some naturalists, 
is a mistake. 
3. It also appears that certain parts which become ossified 
in most kinds of Whalebone-Whales do not become so in 
others. Thus the lateral processes of the cervical vertebrae of 
Meygaptera, Benedenia, and Physalus seem to be nearly of the 
same form in the young and cartilaginous state; that is to say, 
they have the usual form of these bones in the Balenopteride ; 
and though the entire lateral process becomes ossified m Phy- 
salus and Sibbaldus, the end of the process remains cartilaginous 
at least to a much greater age, if not always, in the genera 
Megaptera and Benedenia. Naturalists observing this apparently 
imperfect development of the bones in the latter genus, have 
been induced to believe that it arose from the youth of the spe- 
cimens observed, instead of being a peculiarity of the genera, 
overlooking the fact that the skeletons of the oldest Megaptere 
that have been examined show the same apparently imperfect 
development and truncated form of the bones. 
4. The general form of the baleen, the comparative thickness 
of the enamel, and the fineness or coarseness of the internal 
fibres which form the marginal fringe, and the internal structure 
as shown by the microscope, all present good characters for de- 
termining the species and for separating the Whalebone- Whales 
into natural groups, as I have shown in the ‘ Zoology of the 
Erebus and Terror.’ 
The qualities of the whalebone or baleen from various loca- 
lities, and hence from different kinds of Whales, have been ob- 
served, and have led to their employment for different purposes 
by the handicraftsman ; according to their goodness and rarity, 
they fetch very different prices in the market—an instance of 
