ii2 THE GROUNDWORK OF SCIENCE

for the following reason : Its bell-shaped body is connected

with a fixed point of support by means of an elongated stem,

traversed by a special fibre. At the slightest shock this fibre

contracts, and throwing the filament into curves, draws the

body of the creature near to the point of attachment of

the filament.

The second division of the animal kingdom consists of

creatures the body of each of which is formed by a multi-

tude of cells which are aggregated together into, or give

rise to, various kinds of distinct substances, termed " tissues "

such as bone, gristle, muscle, nerve, etc., etc.

The lowest of these many-celled animals are the sponges,

and the cells which compose their bodies are arranged in two

layers.

Next come the Zoophytes, or plant-like animals (corals,

sea-anemones, jelly-fishes, etc.), to which succeed the star-

fishes, sea-urchins and their allies. A multitude of creatures

compose at least two large groups of worms, of which the

leeches and earth-worms may serve as examples of the higher

kinds. We have then an enormous group, Arthropoda,

which embraces all insects, hundred-legs, scorpions, spiders,

mites, crabs, lobsters, and shrimp-like creatures. We have

again a very much less extensive group of Mollusca, which

includes all snails, whelks, cuttle-fishes, oysters, mussels, etc.

Lastly we have the group of backboned animals (fishes,

reptiles, birds, and beasts), to which we ourselves belong.

Of beasts, or Mammals, there are some dozen different

orders, such as opossums, whales, rats and squirrels, cattle,

bats, beasts of prey, apes, etc.

The structure of man's body closely resembles that of

the higher apes, while apes and man agree to differ so

much from all other Mammals that they may be said to

stand, as it were, on a zoological island by themselves.

Thus man, when only structurally considered, is a species

for the following reason : Its bell-shaped body is connected

with a fixed point of support by means of an elongated stem,

traversed by a special fibre. At the slightest shock this fibre

contracts, and throwing the filament into curves, draws the

body of the creature near to the point of attachment of

the filament.

The second division of the animal kingdom consists of

creatures the body of each of which is formed by a multi-

tude of cells which are aggregated together into, or give

rise to, various kinds of distinct substances, termed " tissues "

such as bone, gristle, muscle, nerve, etc., etc.

The lowest of these many-celled animals are the sponges,

and the cells which compose their bodies are arranged in two

layers.

Next come the Zoophytes, or plant-like animals (corals,

sea-anemones, jelly-fishes, etc.), to which succeed the star-

fishes, sea-urchins and their allies. A multitude of creatures

compose at least two large groups of worms, of which the

leeches and earth-worms may serve as examples of the higher

kinds. We have then an enormous group, Arthropoda,

which embraces all insects, hundred-legs, scorpions, spiders,

mites, crabs, lobsters, and shrimp-like creatures. We have

again a very much less extensive group of Mollusca, which

includes all snails, whelks, cuttle-fishes, oysters, mussels, etc.

Lastly we have the group of backboned animals (fishes,

reptiles, birds, and beasts), to which we ourselves belong.

Of beasts, or Mammals, there are some dozen different

orders, such as opossums, whales, rats and squirrels, cattle,

bats, beasts of prey, apes, etc.

The structure of man's body closely resembles that of

the higher apes, while apes and man agree to differ so

much from all other Mammals that they may be said to

stand, as it were, on a zoological island by themselves.

Thus man, when only structurally considered, is a species