2 THE ZOOLOGIST. 
The order Cetacea has been divided into two very natural 
groups—the Whalebone Whales, Mystacoceti, and the Toothed 
Whales, Odontocett. 
The former are characterized by the absence of teeth and the 
possession in lieu thereof of great plates of horny fibre, called 
“baleen,” depending from the palate, and known as the “ whale- 
bone” of commerce. The latter are destitute of whalebone and 
possess teeth, either in one jaw or both, sometimes few and 
rudimentary, sometimes numerous, and always single-rooted and 
similar to oue another. 
Again, the Whalebone Whales possess olfactory organs, and 
have a double orifice to the blow-hole; the ribs are very slightly 
articulated to the vertebra, and the sternum or breastbone con- 
sists of a single piece, which is attached to the first pair of ribs 
only. 
The Odontoceti, or Toothed Whales, on the contrary, have no 
olfactory nerve; a single external orifice to the blow-hole; the 
anterior ribs more closely united to the vertebra ; and the sternum, 
which, in the young at least, is composed of several segments, is 
attached to several of the ribs. 
The first group, Mystacoceli, may be conveniently Gised into 
two families—the Balenide, to include the Right Whales; and 
the Balenopteride, to include the Hump-backed Whale and the 
Rorquals, or Fin Whales. 
The second group, Odontoceti, have been divided by Professor 
Flower into three families —the Physeteride, to include the 
Cachelots and Ziphioid Whales; the Platanistide, for the recep- 
tion of the long-snouted fresh-water Dolphins of India and South 
America, of which we have no representatives in our waters; and 
the Delphinide, to include the Dolphins and Porpoises, with the 
Narwhal, and the White Whale, or Beluga. 
The following Table will convey some idea of the number and 
variety of the British Cetacea, and will at the same time exhibit, 
to a certain extent, their affinities. The nomenclature adopted is, 
with a few exceptions, where older names seemed to deserve 
priority, that of the second edition of Bell’s ‘ British Quadrupeds,’ 
in which work will be found much useful information on the 
subject of British Whales and Dolphins, and, by way of intro- 
duction, an excellent account of their organization. 
