MAMMALIA. 421 
of whales, and there is a great difference of opinion upon this subject 
among naturalists. This is very natural, as these great cetaceans are 
seldom met with by practical observers, and come ashore at periods of long 
intervals only. Moreover, they cannot be compared directly with one 
another; and their remains cannot be easily preserved, nor their forms 
easily reproduced correctly in drawing. 
Of the genus Balcnoptera, three species seem to be well characterized ; 
B. jubartes, the rorqual, from the northern Atlantic, and from seventy to 
eighty feet in length; B. musculus, from the Mediterranean, and B. ant- 
arctica, from the Cape of Good Hope. Some other species are cited as 
belonging to the northern seas, but are not satisfactorily described, such as 
B. gubbar, seen between Cherie Island and Nova Zembla, B. acuto-rostrata, 
or sharp nosed whale, inhabiting chiefly the Norwegian seas. 
The genus Balena differs from the preceding by its great, thick, and 
obtuse head, in being deprived of the fin-lke expansion of the back, and 
in having the inferior part of the body smooth, that is to say, deprived of 
the longitudinal folds, more or less deep, as seen in Balezenoptera. A single 
species of this genus is adopted by some authors, B. mysticetus, or black 
common Greenland whale (pi. 106, jig. 1), the one constituting the chief 
object of the whale fishery. The head forms one third of the total length. 
The broad jaw extends along the whole length of the head to behind the 
small eyes. The cesophagus is narrow, for which reason the whale can 
swallow small marine animals alone. The color is velvet black, marbled 
with grey and white; the belly is entirely white. It would be highly 
interesting to know. whether the same species of whale be found in all the 
fishing grounds, a question which we may be authorized to doubt, as we 
have some accounts and some facts which indicate a second species around 
the Cape of Good Hope, B. antarctica differing from B. mysticetus in some 
peculiarities.in the structure of the bony head. We are told also, that the 
ice-whale, or £B. islandica, differs from B. mysticetus in having a more 
lengthened body, and a proportionally smaller head. The two spiracles or 
air. holes represent two small semicircles, which are a little separated from 
each other, the convexities of which are opposed. The eye is very small, 
and its shortest diameter is placed obliquely. The general color of B. 
islandica is grey, more or less distinct in its shades. The lower part of 
the head often appears like a great oval of very shining white, at the centre 
and circumference of which are seen grey or black spots, irregular and 
confused. 
Several fossil species of Balena and Balenoptera have been found in 
the tertiary deposits of Europe. The genus Cetotherium is extinct ; its 
remains have been found in the upper tertiary of Russia, and assimilated 
at first to other cetaceans, when the present genus was established and 
placed in the vicinity of Baleenoptera, from which it differs by the broad- 
ness and flatness of the posterior part of the skull, the elevated and thick 
arch, and the deep temporal grooves. (. rathkei is the only species known 
and found in several localities in the Russian empire. 
Balena mysticetus, Greenland or right whale, is most frequently found 
ICONOGRAPHIC ENCYCLOPADIA.— VOL, II, 40 625 
