1000 The American Naturalist. [November, 

‘* great deal of work is done, vastly altering the appearance of the — 
country, by what may appear to many people at first sight a perfectly e a 
ridiculous agency,—viz., the white ants; but after passing over the ; 
plains ór through the thickets, where their hills are so numerous that F 
it is difficult to drive through them, the immense amount of their work S 
can be better appreciated. The clay, cemented with resinous matter, 
with which they build their nests is as hard as brick, and when these 
fall to pieces they form clay flats almost impervious to water, and so 
hard that they will bear a great deal of traffic without being cut up. 
The work of these creatures can be studied in all stages: first in the 
thickets where they are commencing work; then in the more open 
country, where they have got the upper hand of the timber; next on 
the plains, where half the hills will be found deserted ; and lastly on 
the clay flats, where they have almost entirely disappeared and the 
scrub has begun to grow again. Another remarkable thing about these 
nests is the amount of iron they contain, for when a tree has been 
burnt in which they have built a nest there will be found at its base a 
mass of iron clinker, looking just as if it had come out of a furnace.” 

_ More New Mammalia from the Eocene of Patagonia.— 
M. F. Ameghino describes in a new extract from the Revista for 
August, 1891, the results of the last exploration in Patagonia of M. C. 
Ameghino. These consist of no less than 173 species of Mammalia, by 
far the greater number of which are new to science. 
The most interesting novelty described is a new species of a new 
` genus of Quadrumana, which has the dental formula of the Old-World 
monkeys, with especial resemblances to that of man, This is seen 
especially in the small canine teeth, which are not followed by a dias- 
tema. This genus accentuates the proposition which I have advanced, 
that the line of the Anthropoid apes and man has been derived directly ` 
from the Anthropoid lemur Anaptomorphus of the Eocene period. 
The Homnuculus patagonicus, as this remarkable form is called by 
: Ameghino, certainly has considerable resemblance to the former genus, 
—__~ ~but is more like the true monkeys in its quadritubercular lophodont 
molars. 
The Mammalia described are referable to the on orders : 
bea Nie Py page 
Eden Sei ee he 
lires des wa ee oe et RS 
‘Bunotheria (Insectivora) hee A a 
ae a a a a 
Se po ee 6 6 ea ee 
Taxeopoda (Litopterna) . . 
mana) ; 
soso -ca onn nS 
śŚ 

