50 ON THE NERVOUS SYSTEM IV. 



FIG. 7. Longitudinal section of the brain, a little to the left of the median line. The corpus striatum, 

 C, is here exposed to view, also the body within the optic lobes, G. 



FIG. 8. Longitudinal section of the same on the median line ; the cut surfaces are shaded. L is the 

 entrance to the lateral ventricle, and the space between this opening and the olfactory lobes, A, indicates 

 the extent of the fissure which extends from the upper to the under surface, completely separating the 

 cerebral lobes from each other. 



FIG. 9. A plan, showing the connection between the spinal chord and the different portions of the brain. 

 FIG. 10. Nerve cells or vesicles from the cerebral lobes. 



FIG. 11. Pineal body, consisting almost wholly of loops of bloodvessels ; the whole surface is covered 

 with cilated epithelium, as at a. 



FIG. 12. A small portion of the pineal body, magnified, showing an inclosed loop of bloodvessel, and 

 the epithelial covering. 



FIG. 13. A small portion of chord from the median line, showing the nerve tubes which pass from one 

 side to the other in the gray substance. 



FIG. 14. A small portion of the chord highly magnified, showing the entrance of one of the roots of a 

 spinal nerve, as seen on the surface. 



FIGS. 15 and 16. Portions of the chord from the tail of a tadpole, showing the existence of a central 

 mass of cells with white columns on each side ; the nerve roots enter these last, and ascend towards the 

 trunk. A few transverse fibres only are seen. 



FIG. 17. The under surface of the lower jaw, and sublignal region of a Frog. M, lower jaw; V and 

 V, branches of the facial portion of the trigeminus ; the same as i, k, and h, Fig. 2, Plate II. 



FIG. 18. Calcareous crystals from the crystal capsules of the spinal nerves. 



PLATE II. 



' FIG. 1. General view of the spinal nerves, of the natural size. 2, brachial nerves, a, anastomosing 

 filament from the third spinal nerve, forming a simple brachial plexus. The three following nerves are 

 distributed to the walls of the abdomen. 7, 8, 9, lumbar nerves ; c, union of the 8th and 9th with a 

 branch from the 7th, forming the single sciatic trunk ; e, gluteal nerve ; /, nerve to muscles of the thigh ; 

 g, branches of the crural nerve, distributed to the skin of the thigh ; A, tibial, and i, peroneal nerves. 



FIG. 2. Some of the details of the distribution of the trigeminus (V.) and vagus (VII.) nerves, a, or- 

 bitar branch of trigeminus ; J, palatine branch ; c, terminal branches to vomerine teeth and internal nasal 

 opening ; d, anastomosing branch to upper maxillary nerve ; e, upper and lower maxillary nerves united ; 

 g, " facial," formed by the union of a branch from the trigeminus and vagus nerves ; A, tympanic branch ; 

 t, jugular branch ; k, lower jaw branch ; the last two are the same as V and V, Plate I. Fig. 17 ; /, n, 

 branch of vagus to heart, lungs, and stomach ; m, glosso-pharyngeal. 



FIG. 3. Side view of the branches of the trigeminus. a, orbitar branch ; J, palatine branch ; c, fila- 

 ments to inner nasal orifice ; d, union of palatine and upper maxillary branches ; e, upper maxillary 

 nerve ; /, lower*maxillary nerve ; g, " facial." 



FIG. 4. Right eye seen from above. III. Motor communis entering superior and internal rectus mus- 

 cles. IV. Patheticus distributed to the superior oblique muscles. V*. (on the left of the figure), orbitar 

 branch of trigeminus (should be marked V.) ; V'. (on the right), the alducens, which is a branch of 

 the trigeminus, distributed to the external rectus. 



FIG. 5. IV. Patheticus. V. Orbitar branch of the trigeminus, from which a filament is given off, cross- 

 ing the preceding, and which appears to communicate with it. 



