According as the shell of the testace. ous molluscs consists of a single convo luted tube, or of two or more separate pieces, they are called cochlea: bivalves; multivalves, &c.
Crustacea possess a hard external co vering, and numerous articulated mem bers; a long nervous chord, beset with ganglia; compound eyes ; antennae and palpi like those of insects ; a heart and circulating vessels, and gills ; teeth in the cavity of the stomach.
1. Cancer, crab, lobster, crayfish, shrimp.
2. Monoculus.
Insects have articulated members and antennae. Those which fly are subject to what is called a metamorphosis ; they pass through certain intermediate states of existence before they assume the last or perfect form. From the egg proceeds the larva, or caterpillar : this changes to the chrysalis, nymphs, or aurelia, from which the perfect insect is produced ; nervous system consisting of a chord be set with ganglia; no heart nor blood-ves sels ; respiration carried on by means of tracheae.
Order I. Coleoptera ; having a hollow, horny case, under which the wings are folded. • 1. Scarabxus, beetles.
2. Lucanus, stag-beetle.
3. Dermestes. • 4. Coccinella, lady-bird.
5. Curculio, weevil.
6. Lampyris, glow-worm.
7. Meloe, Spanish-fly.
8. Staphylinus.
9. Forficula, earwig.
II. Hendptera ; four wings, either stretched straight out, or resting across each other.
1. Blatta, cockroach.
2. Gryllus, locust, grasshopper.
3. Fulgora, lantern-fly.
4. Cimex, bug, &c.
III. Lepidoptera ; soft hairy body, and four expanded wings.
1. Papilio, butterfly.
2. Sphinx, 3. phaixna moths_ IV. N'europtera ; four reticulated wings.
1. Libellula, dragon-fly.
2. Ephemera, &c.
V. Hymenoptera ; generally possessing a sting.
1. Vespa, wasp, hornet 2. Aspis, bee.
3. Formica, ant.
4. Termes, white ant.
5. Ichneumon, &c.
VI. Diptera ; two wings.
1. (Estrus, gad-fly.
2. Musca, common flies.
3. Culex, gnat, mosquito.
4. Hippobosca, horse-leech, &c VII. .Rpterh ; no wings.
1. Podura, springtail.
2. Pediculus, louse.
3. Pulex, flea, chigger.
4. Acarus, tick, mite.
5. Aranea, spider.
6. Scorpio, scorpion, &c.
The vermes may be divided into two orders ; the intestinal, which inha bit the bodies of other animals ; and the external.
The former are not of such a compli cated organization as the latter ; so that they are sometimes arranged among the zoophytes. The external worms have a nervous chord possessing ganglia, an elongated body composed of rings, and having no distinct head ; there are no members ; circulating vessels, but no heart ; no nerves have been discovered in the intestinal worms.
Order I. Intestine.
1. Gordius, guinea-worm.
2. Ascaris, thread-worm, round worrit 3. Tricocephalus.
4. Fasciola, fluke.
5. Taenia, tape-worm.
6. Hydatis,,hydatid.
H. Externi.
1. Aphrodite, sea-mouse.
2. Sipunculus.
3. Hirudo, leech.
4. Nereis.
5. Nais.
6. Planaria.
7. Lumbricus, earth. worm, &c.
The Zoophytes have neither brain nor serves; no heart, nor, perhaps, blood.ves ;els ; no articulated members.
Order. I. Echinodermata ; covered by a lard and tough coriaceous skirl.
1. Echinus, sea hedge-hog.
2. Asterias, star fish, &c.
IT. Soft or Gelatinous Zoophytes.
1. lkledusa, sea-blubber, sea net tles.
2. Actinia, sea-anemone.
3. Hydra, fresh water polype.
III. Infusoria, the animalcules of info lions.
1. Vorticella, wheel-animal.
2. Brachionus.
3. Vibrio, eel of vinegar.
4. Volvox.
5. Monas.
IV. Inhabitants of corals, corallines, sponges, &c.