sessing teeth which have been classed by Professor Owen as incisor, canine, and molar. Their remains have been found in supposed Triassic rocks in South Africa.

AVES, birds.-This important section of the animal kingdom has been but sparingly found in the fossil state. The facility with which birds can escape by flight from the destruction that befalls other land-animals will no doubt suffice to explain why their fossil remains should be so infrequent. The oldest known birds had curious reptilian affinities, being furnished with jaws and teeth. Taking all the known forms of birds, recent and fossil, they may be grouped in the following subdivisions :—

I.. Saururæ-in this singular extinct group the vertebral column was prolonged into a long lizard-like tail, each vertebra of which, however, bore a couple of quill-feathers. The only known example is the Archæopteryx of the Jurassic system—the oldest bird yet discovered (Fig. 182).

II. Odontornithes or toothed birds. Some of these (Odontolca) were diving birds with rudimentary wings, ratite sternum, powerful legs, a strong tail for steering, and jaws with numerous conical teeth sunk in a deep continuous groove (Hesperornis). Others (Odontotorma) were provided with strong wings and carinate sternum, and had their teeth sunk in separate sockets, as in the crocodiles. The toothed birds have long been extinct. They have been found most abundantly in the Cretaceous rocks of Kansas.

etc.

strata.

III. Ratite-the cursores or running birds, such as the ostrich, casso-
wary, rhea, emeu, and apteryx. These have not with certainty been
found fossil in strata older than the Tertiary series. The gigantic
extinct Dinornis of New Zealand belongs to this class.
IV. Carinatæ-generally possessing powers of flight. These include
most of the birds of the present day. The arrangement of this great
sub-class into definite orders has not been yet satisfactorily accom-
plished. The student, however, may find some advantage in making
himself acquainted with the following names which, though in process
of being superseded, are still in common use. Natatores-swimmers
or palmipeds, with short legs placed behind and provided with webbed
feet. These include gulls, penguins, geese, ducks, swans, cormorants,
Remains of this order are found in Cretaceous and Tertiary
Grallatores-waders, chiefly found by the shores of rivers,
lakes, or the sea, distinguished by the length of their legs, which are
not completely webbed. They include plovers, cranes, flamingoes,
storks, herons, snipes, etc. They have been found fossil in Cretaceous
and Tertiary rocks. Rasores-scratchers or gallinaceous birds,
including the various tribes of fowls and pigeons. They are found
fossil in Tertiary strata. Scansores-climbers, including the parrots,
cuckoos, toucans, and trogons. They are only found fossil in Tertiary
and Post-tertiary rocks. Insessores-perchers, passerine birds in-
clude by far the largest number of living birds, and all the ordinary
song-birds. They have not been met with in a fossil state in rocks
older than the Tertiary series. Raptores or birds of prey, comprising
birds with strong, curved, sharp-edged, and pointed bills, and strong
talons, as the eagles, hawks, falcons, vultures, and owls. This order
also has not been obtained fossil except in Tertiary and Post-tertiary
rocks.

MAMMALIA.-The highest class of the vertebrata is represented chiefly on the land, the marine representatives being few in number, though often of large size (whales, dolphins, porpoises, manatee, seals, morse). In marine deposits, therefore, we need not expect to find mammalian remains abundant at the present time. Doubtless from the time of their first appearance mammals have always been, on the whole, terrestrial animals; their fossil remains consequently occur but sparingly among ancient geological formations. The earliest known examples belong to the Marsupial type, and have been found in the Triassic and Jurassic rocks of Europe and North America.

I. PROTOTHERIA or ORNITHODELPHIA—including the two types of Ornithorhynchus and Echidna.

II. METATHERIA or DIDELPHIA-Marsupial animals. Comprising the Opossums (Didelphidae), Dasyures, Myrmecobius, Perameles, Kangaroos, and Wombats. As just mentioned, it is representatives of this section of the vertebrates that occur fossil among the Mesozoic rocks [Microlestes, Fig. 170, Dromatherium, Amphitherium, Phascolotherium, Fig. 183].

III. EUTHERIA or MONODELPHIA—including the vast majority of living and extinct mammalia. They may be grouped as follows :—

Edentata-sloths, ant-eaters, armadilloes, pangolins, and African ant-
eaters. Some enormous extinct types of Edentates have been found
in America [Megatherium, Mylodon, Moropus, Glyptodon].
Sirenia-aquatic fish-like animals including the manatee, dugong, sea-
COW. The last named is now extinct, the last having been killed so
recently as 1768. Numerous fossil remains of Sirenians occur in
Miocene and Pliocene deposits of Europe [Halitherium].
Cetacea-whales including the Balænidæ or whalebone whales, Delphi-
noidea or toothed whales (Sperm whale, Ziphius, Narwhal, Porpoise,
Ca'ing whale, Grampus, Dolphin). Cetacean ear-bones and other bones
are not infrequent in Tertiary and Post-tertiary strata.

Insectivora-small terrestrial mammals like the shrews, moles, myogale.
No fossil insectivores older than Eocene times are known, except
perhaps Stereognathus of the Stonesfield slate.

Cheiroptera-animals with the fore-limbs adapted for flight, including
the tribe of bats. Fossil representatives are found as far back as
Eocene rocks.

Rodentia-small terrestrial plant-eating mammals, distinguished by their
large chisel-shaped incisor teeth, specially adapted for gnawing, and
by the absence of canines. Among them are squirrels, marmots,
beavers, dormice, rats, mice, voles, lemmings, jumping mice, jerboas,
porcupines, chinchillas, cavies, rabbits, and hares. Fossil rodents
belonging to most of the existing families have been met with in
Tertiary and Recent strata, together with some extinct types.
Ungulata or hoofed animals include the Hyrax, the Proboscideans
(elephants, Fig. 205, and the extinct types of Mastodon, Fig. 199,
Deinotherium, Fig. 200, etc.) and the extinct type of the Deinocerata
(Fig. 196); the perissodactyl or odd-toed group (tapirs, rhinoceroses,
horses, [Palæotherium], Fig. 195), and the artiodactyl or even-toed
group (hippopotamus, peccary, swine, llama, camel, chevrotains, the
true ruminants, such as deer, antelopes, giraffes, [Helladotherium, Fig.
203], and all bovine animals). The earliest known forms are of
Eocene age.

Carnivora-so named from the majority of them subsisting on animal

food and being eminently beasts of prey. They are divided into (1) Fissipedes or true carnivores, generally adapted for life on land, comprising (a) the Æluroids or cat-like forms (lions, tigers, cats, puma, jaguar, cheetah, civet-cat, ichneumon, hyæna, and various fossil forms found in Tertiary and Post-tertiary deposits); (b) the Cynoids or doglike forms (dogs, wolves, foxes); and (c) the Arctoids or bears and their allies (otters, badgers, weasels, raccoons, panda); (2) Pinnipedes or aquatic carnivores, divisible into three well-marked families: (a) Otariids or sea-bears; (b) Trichechids or walruses; (c) Phocids or true seals.

Primates, the highest division of vertebrate life, comprising (1) the Lemuroid animals; (2) the Hapalids or marmosets; (3) the Cebids or American monkeys; (4) the Cercopithecids, the monkeys of the Old World, exclusive of the apes; (5) the Simiids or man-like apes (Troglodytes, Gorilla, Simia, and Hylobates); (6) Man.

INDEX

An asterisk (*) denotes that a figure of the subject will be found on the page indicated.