12. Guide to Whales, Porpotses, and Dolphins. 
family, Balenide, and are divided into five genera, the most 
striking distinguishing characters of which are as follows :— 
A. Skin of the throat smooth. 
a. Whalebone long, slender and elastic: all the neck, or 
cervical, vertebra united together. 
(a) No back-fin; flippers broad (five-fingered) : 
Balena, Riaut- WHALES, 
(b) A small, falcate (sickle-shaped) back-fin ; flipper 
narrow (four-fingered): Neobalena, Piamy 
WHALE. 
b. Whalebone very short and coarse: vertebra of the neck 
free: no back-fin: Rhachianectes, GREY WHALE. 
B. Skin of the throat furrowed: whalebone short and coarse. 
a. Flippers very long: a low, rounded back-fin: Megaptera, 
Hump-pack WHALE. 
b. Flippers small: a triangular, faleate back-fin: Balzno- 
ptera, Rorquaus or Fry- WHALES. 
Neobalena and Rhachianectes are each represented by a single 
species, the former confined to the Southern Seas and the latter 
to the North Pacific. The other genera are widely distributed ; 
there are certainly two very distinct kinds of Balena, at least four 
of Balenoptera, perhaps only one of Megaptera. 
Right-Whales. These ea (genus Balen) are distinguished 
from other Whalebone-Whales by the dispro- 
portionately large size, and especially the great height, of the 
head, as well as by the absence of a back-fin, and of furrows in 
the skin of the throat. Notwithstanding their enormous bulk, they 
appear not to exceed about fifty feet in length. The comparative 
facility with which they are caught, the length and fine quality of 
their whalebone, and the great quantity of oil they yield have 
given rise to the name by which they are usually designated by 
whalers, in contradistinction to Rorquals and other less valuable 
species. They feed upon very minute crustaceans and pteropods, 
which swarm in immense shoals in the seas they frequent ; 
specimens of such ‘ Whale-food ” are exhibited in glass jars on the 
east wall of the Whale-room. The females are larger than the males. 
There are two very distinct types of Right-Whale. Firstly, the 
Greenland or Arctic Right-Whale (Balena mysticetus, fig. 2) of the 
