The anti-monopolist. [volume] (Saint Paul, Minn.) 1874-1878, 1877-10-18

northern to the southern continent OF
America, there found more
congenial home. and there in time
became extinct. In the middle eocene,
west Of the Rocky Mountains,
THE DINOCERATA.
a remarkable group Of ungulates,
made it's appearance. Nearly equal
ling the elephant in size, this animal
had shorter limbs, while arming it's
skull were two or three pairs OF hOrd-
cones, besides enormous canine tusks.
In the lower eocene appeared the
progenitor Of the horse, the eohippus.
about the size of a fox and having
we'll developed toes. In the lowest
eocene appear the artrodactyles, the
ancestor Of the pig, and in the upper
eocene comes the oromeryx. whence
probably sprang the deer.
THE PRIMATEs AND MAN.
We come now to the highest group
of mammals, the primates, which
includes the lemurs, the apes, and
man. This order has great antiquity,
and even at the base of the eOcene we
find it represented by several genera
BELONGING to the lower forms OF the
group. In considering these interest
ing fossils, it is important to have in
mind that the lemurs, which are
usually regarded as primates, although
at the bottom of the scale, are only
Efound at the present day in Madagas-
car and the adjacent regions OF the
globe. All the American monkeys,
moreover, belong to one group. much
above the lemurs, while the Old
World apes are higher still. and most
nearly approach man.
In the lower eocene of New Mexico
we find a few representatives OF the
earliest known primates, and among
them are the genera Iemurdous and
Hmnotherium, each the type OF a
distinct family.
The oldest known remains OF man
on this continent differ IN no lmpor'
tant characters from the bones OF the
typical Indian, although in some
minor details they indicate much
more primitive race. These early re
mains. some of which are true fossils
resemble much more closely the cor
!, responding parts Of the highest Olt
World apes, than do the latter oul
J tertiary primates, or even the Tecen
| American monkeys. Various living
, and fossil forms of Old World prlmate'
; fill up essentially the latter gap. Th'
lesser gap between the primitive maj
of America and the anthropoid ape
is partially closed by still lower forms
of men. and doubtless also by hlghe
apes, now extinct.
The real progress of MAMMALIAN lit
in America, from the beginning o
the tertiary to the present. is wei
illustrated by the brain-groWth, II
which we have the key to many othe
: changes. The earliest known tertlar.
mammals all had very small brains
and in some forms this organ wa
proportionately less than in certain
reptiles. There was gradualincreas'
: in the size of the brain during thl
, period, and it is interesting to fint
that this growth was mainly confined
to the cerebral hemispheres, or hlghe
r portion of the brain. In most group
of mammals the brain has gradual.
become more convoluted and thus IN
, crease in quality as we'll as quantity
, In some. also, the cerebellum an
olfactorv lobes. the lower parts 0
i, brain. have even diminished in size
, In the long struggle for eXistenc
: during the tertiary time the bl
e brains won. then as now; and tn
:. increasing power thus gained rendere
q useless many structures lnherlte
o from primitive ancestors, but II
longer adapted to new conditions.
! Another of the interesting change
q in manuals during tertiary time was
: the teeth, which were gradual
= modified with other parts of tn
; structure. The primitive form Q
! tooth was clearly a cone, and a
: others are derived from this. A
: classes of vertebrates below mammals
: namely. fishes, amphibians, reptiles
q and birds, have conical teeth, II any
: or some simple modification OF TIL
: form. The edentates and cetacean
q with teeth retain this type, excep
q the Zeuglodonts, which approach th
dentition Of aquatic carnlyOres. l
the higher mammals, the inclSors an
e CANNES retain. the conical shape, an
= the premolars have only in part bee
> transformed. The latter gradual
! change to the more complicated mola
" pattern. and hence are not reduce
! molars, but transition forms from tn
y cone to more complex types. Most
) the early tertiary mammals had fort.
# four teeth. and in the oldest forms tn
- nremolars were all unlike the molar
q while the crowns were short, covere
# with enamel, and without cemen
d Each stage of progress in the diffe
' entiation of the animal was. as rul
e marked by change in the teeth; OF
i of the most common being the tran
n fer. in form at least, of premols
re to the molar series, and a gradu
le lengthening of the crown. Hence,
le is often easy to decide from fra
# ment of jaw to what horizon of tt
le tertiary it belongs. The fossil hors
" of this period, for example, gained
grinding tooth, for each toe they 10
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