PRIMARY GROUPS OF MAMMALS. 527 
on the collections of the Smithsonian Institution for his investiga- 
tions, he has also visited the museums of the Academy of Natu- 
ral Sciences of Philadelphia, the Peabody Academy of Science of 
Salem, the Boston Society of Natural History, and the Museum 
of Comparative Zoology at.Cambridge. 
The relations of the several primary groups of the class may be 
more readily understood from a glance at the subjoined table, 
which will also serve as a genealogical table for those who accept 
the doctrine of evolution. The more generalized forms—and 
therefore the quasi-eldest—are represented by the left branches. 
It may not be entirely superfluous to remark that adaptive special 
modifications must be subordinated to morphological in every 
case: it will therefore be understood that although the Cetacean 
is, in a teleological sense, the most specialized form of mammals, 
it is a divergent from the same common stock as the Carnivores 
and other Educabilia, and must be contrasted morphologically with 
them alone and not with the rest of the mammals; the bat, an- 
other extremely specialized form, is in like manner a derivative 
from the same common stock as the Insectivores, and therefore to 
be contrasted with them alone. 
N 
o> ` 
ee om 
ORNITHODELPHIA. | 
DIDELPHIA. 
aera > 
m | 
et ee ` ane ETS 
E | E 
(Edentate Series.) (Mutilate Series.) 
BRUTA. -—-_ooo | 
p a A 
| I 
(Insectivorous Series.) (Rodent Series.) 
GLIRES. 
| 
(Primate Series.) 
PRIMATES. 
2 x $ BIRENIA. CETE. 
| | 
INSECTIVORA. CHIROPTERA. ‘ 
ARE heer ` 
| : l. 
(Ungulate Series.) (Feral Series.) 
| FER. 
| | | pE 
PROBOSCIDEA. HYRACOIDEA, TOXODONTIA. UNGULATA. 
CLASS MAMMALIA. 
Abranchiate Vertebrates with a brain whose cerebral hemispheres are 
more or less connected (and in nearly inverse ratio) by an anterior com- 
+ 
