514 REMARKS ON THE CLASSIFICATION OF MAMMALIA. 
test of the characters of orders, and whilst a common plan, and cor- 
respondence in certain important particulars are deemed a sufficient 
justification for uniting intestinal worms with anellida, and Epizoa 
Cirrhipeda and even Rotifera with Crustacea, it would afford no reason 
for combining the Sarcophagous Marsupials with Carnivora, the 
vegetable feeders with Rodentia, or the Monotremata with Edentata. 
I must confess that I look upon orders as minor classes ; groups which | 
are, like the classes and all other useful divisions, really marked in 
nature, so that in laying them down we are interpreting nature, but 
which differ from the classes rather in the extent and importance of 
the characters than in their essential qualities. If we look at examples 
amongst the best marked and most generally recognised orders, we 
shall, I think, find abundant justification for this view. I cannot 
consider the various tribes of mammals without being impressed with 
the feeling that if the received order Rodentia be placed in the centre, 
Insectivora, Cheiroptera, Edentata, and the Marsupial tribes corres- 
ponding to two of these, and to the tribes included in Rodentia, are all 
closely associated together, differing from each other only in the same 
degree as among birds the Dentirostres, Fissirostres and Tenuirostres 
differ from the Conirostres. Here then I find the great centre groups 
of mammals typically represented by the carnivorous and herbivorous - 
Rodentia, and making approaches in various directions to the great 
deviative classes. Of these Quadrumana represent Scansores among 
birds; Carnivora Raptores; Ruminantia, Rasores; Pachydermata, 
Grallatores; Cetacea, Natatores. Within the great centre group 
Insectivora represent Dentirostres ; Cheiroptera, Fissirostres; Eden- 
tata, Tenuirostres. The kangaroos in their intermediate position 
between the family Leporida of Rodentia and the Ruminantia, corres- 
pond well with Columbidz among birds. _'The Camelida form a link 
between Ruminantia and Pachydermata of the same kind that the 
Ostrich forms between Rasores and Grallatores ; and the Hippopota- 
mus and the Manatida or sea-cows connect Pachydermata with 
Cetacea much as the Flamingo does Grallatores and Natatores. Unwill- 
ing to trespass on your time, and to trouble you with details that. 
might prove tiresome, I confine myself here to a general statement of 
my plan, but it seems to me that whilst expressing the affinities of. 
mammals more clearly and naturally than is done by the prevalent 
systems, there is no small advantage gained by the beautiful correspond- 
ence maintained between the arrangement of mammals and birds, and 
