EXPLANATION OF THE FIGURES.

THE figure of the brain of the turtle is from Bojanus, and that of the monkey from Tiedemann, the rest are from nature. Of the vignettes the first is from Gio. Pichler, the six following from the Greek, and the last from a tablet by Wedgwood and Flaxman. They all relate to the myth of Esculapius.

PLATE I.

FIGURE 1. Supposed nervous system of a radiated animal (asterias rubens). 2. Ditto of an ascaris from the horse. 3. Nervous system of a species of siphunculus from the West Indies. 4. Interior of the œsophagus of the same. 5. Termination of the intestinal canal of a similar species. 6. Nervous system of the sea-mouse (aphrodite aculeata). 7. Portion of the nervous cord magnified. 8. Nervous system of a large species of dragon-fly (libellula).

PLATE II.

FIG. 1. Nervous system of an ascidia. 2. Ditto of a cockle (cardium echinatum). 3. Ditto of a doris. 4. Ditto of a limpet (patella vulgaris). 5. Ditto of a shell-snail (helix nemoralis). 6. Ditto of bullæa aperta. 7. Nervous system of the cuttle-fish (sepia officinalis). 8. Brain of ditto. C. Cerebral ganglia. B. Branchial ganglia. P. Pedal or motor ganglia. L. Labial ganglia. M. Maxillary ganglia. S. Sympathetic ganglia. 2. Optic nerves. a. Branchial nerves. b. Ditto of mantle. c. Ditto of

fin.

PLATE III.

FIG. 1. Nervous system of the cod (morrhua vulgaris). 2. Structure of the brain below. 3. Ditto above. 4. Pituitary body, &c. 5. Brain of a small species of lamprey (petromyzon Planeri). 6. The same seen from below.

C. Cerebral lobes. L. Cerebellum. O. Optic lobes. P. Pituitary body. 1. Olfactory nerves. 2. Optic nerves. 3. Motores oculorum. 4. Fourth pair. 5'. Ophthalmic nerves of fifth pair. 5". Superior maxillary ditto. 5". Inferior ditto. 6. Sixth nerves. 7'. Facial nerves. 7". Acoustic nerves. 8'. Glosso-pharyngeal nerves. 8" Nervi vagi. 8"". Spinal accessory. 9. Hypoglossal nerves.

[The above letters and figures refer also to the following plates.]

FIG. 1. a. Branches of vagus going to the sides of the animal. b. Visceral nerves. c. Nerve going to the palate. d. Large nerve supplying the opening of the gill-flap, the fins, and the sides of the fish, anastomosing with the spinal nerves. e. Small branch of the fifth supplying the floor of the mouth, cheek, and lower jaw. f. Ditto given to the orbit and integuments over the lip. g. Nerve to the muscles below the eye. h. A small nerve to the palate. In FIG. 2, fibres are represented as rising from the spinal cord and forming the different cephalic ganglia. In FIG. 3, the internal prominence of the optic lobes is formed by a lamina from the cerebellum, their external coats are formed by the optic nerves.

PLATE IV.

FIG. 1. Nervous system of the common frog. 2. Under surface of its brain. 3. Brain of the tortoise. 4. Brain of a species of harmless snake. 5. Under surface of the same. 6. Brain of the cuckoo. 7. Under surface of ditto dissected, the pituitary body being lodged with the arteries in a bony bifurcated canal. 8. Upper surface of the brain of the goose. 9. Lower ditto. 10. Cerebrum displayed internally. 11. Pituitary body.

PLATE V.

FIG. 1. Brain of a hare, under surface. 2. Ditto, upper surface. 3. Corpora quadrigemina, or optic lobes displayed; i. posterior commissure; j. anterior ditto. 4. Brain of the squirrel. 5. Ditto of the mole. 6. Under surface of ditto. 7. Internal structure of ditto. 8. Brain of the common bat (verpertilio pipistrellus). 9. Under surface of ditto, with the acoustic nerve entering the cochlea. 10. Brain of the weasel (mustela vulgaris). 11. Under surface of ditto. 12. Brain of the hedgehog. 13. Upper surface of ditto.

PLATE VI.

FIG. 1. Brain of the terrier dog. 2 Side view of ditto. 3. Brain of the domestic cat. 4. Brain of the fox, seen above. 5. Ditto, seen below. These figures are somewhat reduced.