170 Zoological Society :— 
B. The front lobe of the sternum broad ; side curved outwards, with 
a large pair of gular shields produced at the outer angles; the 
sides and the margin strongly dentated. Kiniays, 
1. Krnixys erosa. The fifth vertebral plate rounded; nuchal 
none. 
2. Kinrxys Homrana. The fifth vertebral plate produced, an- 
gular; nuchal plate distinct. 
On THE ARRANGEMENT OF THE CETACEANS. 
By Dr. Joun Epwarp Gray, F.R.S., ETc. 
In the part of the ‘ Zoology of the Erebus and Terror’ devoted to 
the Cetacea I collected together all the materials within my reach, and 
published an arrangement of the genera, and notes on all the species, 
of these animals which were then known to me, either from the 
examination of the specimens in different museums, or from the de- 
scriptions and observations in various zoological and whaling works. 
The first part of the ‘ Catalogue of the Specimens of Mammalia in 
the Collection of the British Museum,’ which is devoted to the 
Cetacea (published in 1850), may be considered as a revision of the 
former essay, with the additional material that I had been able to 
collect since it had been penned. During the thirteen years that 
have elapsed since the publication of the Catalogue, I have not 
allowed any opportunity to escape of examining and comparing the 
different specimens which have come under my observation, and I 
have read with care all the papers and works that I have been able 
to meet with bearing in any way on Whales and their allies. I am 
now induced to lay the results, as far as the general arrangement of 
the order is concerned, before the Society. 
Some zoologists pay little regard to such re-arrangements of genera 
and the division of them into groups; but this arises from the points 
of view from which they regard them. If they look on them as 
only artificial keys to discover the name of a genus, and thus arrive 
at the name of a species, and if that is the object of the person who 
forms them, then they are perhaps estimated at their right value. 
But I have laboured at these and other arrangements which I haye 
' suggested with a very different view. If it is considered desirable 
to place the species in natural groups called genera, it is certainly 
equally desirable that the genera so formed should be disposed in 
the larger and larger groups in such an order as appears to the writer 
most distinctly to exhibit the natural relations which the genera bear 
to each other. If they are so disposed, then the name that is given 
to a group of species is of little importance, as to whether the group 
is called a genus or subgenus, a genus or subfamily, or a family. 
They may be so regarded at the caprice or theory of the student, as, 
whatever may be their nominal value, they are intended to represent 
a natural group of species, arranged together so as best to represent, 
according to the writer’s view, the natural relation of the species 
to each other. 
—s, 
SD ee 
