Читать книгу Four-Footed Americans and Their Kin - Mabel Osgood Wright - Страница 10

Table of Contents

	Protozoa orFirst Animals	The trunk. The lowest form of animal life, body; a single cell. Most of them too small to be seen without microscope.
1.	Sponges	Plant-like water animals that cannot move.
2.	Jelly Fishes	Round masses of clear, jelly-like stuff floating in the sea. Sea Anemones, etc.
3.	Corals	The white, lace-like specimens that you have seen in cabinets, or the polished pink sprays that are made into ornaments or carved into beads. You may have thought these some sort of stones, but corals are tiny, soft-bodied animals living in cases made of lime. Many of these cases built up close together form the beautiful shapes that you know.
4.	Star Fishes	The five-pointed prickly animals found on sea beaches. Sea Urchins, etc. Crinoids, etc.
5.	Worms	Long squirming animals, of both land and water; also living as parasites upon the insides of other animals.
6.	Mollusks	Shell Fish, such as Oysters, Clams and Mussels, Snails, Slugs, Cuttle Fish, etc.
7.	Crustaceans	Animals covered with a hard shell, having many legs and a pair of feelers, or antennæ, breathing through gills the air that is dissolved in the water. Lobsters, Crabs, etc., are Crustaceans.
8.	Spiders and Scorpions	(Called Arachnidæ, from Arachne, the Spinner, because they spin webs.) Are a sort of cousin to Crabs, but live on the earth instead of in the water.

"The top branches of this group contain the Insects, with many legs, their bodies being divided into three parts. Insects go through many changes in the course of development. Take the butterfly as an example. First an egg is laid by a fully grown butterfly; second, a caterpillar is hatched from the egg; third, the caterpillar spins itself into a chrysalis, or cocoon, out of which comes the winged butterfly. Ants, mosquitoes, flies, and beetles are all insects.

"Among the next circle of branches we find the animals having backbones, the Vertebrates. I think you will feel more at home with them, and we are more nearly concerned with them now, as our mammals belong in this order, although there are many things you must some day learn of the many backboneless twigs, especially about the insects with their wonderful wings and stings."

"I suppose my Rattlesnake is a rather low-down Vertebrate, Uncle Roy," said Nat.

"No, my boy, there are two grades below him and two above. See,"—and the Doctor drew a branch with five divisions.

Vertebrate Branches of the Animal Tree.