888 The American Naturalist. [ November, 
Sclater’s first system, by the union of his three divisions of Ne- 
arctic, Palearctic and Indian into one, for which the name 
Arctogea is appropriate. The enclosure of his Ethiopian divis- 
ion in it as proposed by Huxley, does not seem to me to be 
proper, in view of the important types of fishes and reptiles 
which characterize it; e. g., the Crossopterygian, Dipnoan and 
Seyphophorous fishes, and the Pleurodire tortoises. In the 
fishes, indeed, the Ethiopian region has as much affinity with 
the Neotropical fauna as with any other, in its Characin and 
and Cichlid families, and in the Dipnoan subclass. The pres- 
ence of the Dipnoi and the Pleurodire tortoises ally it to the 
Australian fauna as well. It is for these reasons that Prof. Gill 
proposes to combine the southern hemisphere realms into a 
single “ Eogaean” division. The northern affinities of the 
Ethiopian realm are, however, too many to permit us to regard 
this arrangement as a just expression of the facts. Thus, it 
has Insectivorous Mammalia, Firmisternial Batrachia Anura, 
and Cyprinid fishes, none of which are Australian or Neotropi- 
cal types. The course that remains under the circumstances is 
to regard the Ethiopian Realm as fully distinct from the other 
three. The definitions of the four primary divisions are then 
as follows: 
The Australian realm is peculiar in the absence of nearly all 
types of Mammalia, except the Ornithodelphia and the Marsup- 
ials; in the presence of various Ratite birds, in great develop- 
ment of the Proteroglyph serpents, and absence of the higher 
division of both snakes and frogs; i. e., Solenoglypha and Firmis- 
ternia; in the existence of Dipnoi (Ceratodus) and certain Isospon- 
dylous families of fishes. On the other hand many of the liz- 
ards and birds are of the higher types that prevail in India 
and Africa, viz.: the Agamide and the Oscines. 
The Neotropical realm only possesses exclusively the Pla- 
tyrhine monkeysand the great majority of the humming birds. 
It shares with the other Southern regions the Edentate and 
Tapiroid mammals; Ratite, Pullastrine, and Clamatorial birds; 
Proteroglyph snakes; Iguanid Lacertilia, the Agamids being 
entirely absent; Arciferous frogs ; and Characin, Chromid, Os- 
teoglossid, and Dipnoan fishes. It has but few types of the 
