550 FRANGIS VILLY. 
anterior cornu of the hyoid is shown at different levels on the two sides. 
(x 8.) 
Fic. 18.—Diagrammatic horizontal section of an adult frog’s head. The 
length of the recessus is shown on the right, and the columella and stapes 
are in position, On the left an attempt has been made to show the distribu- 
tion of the auditory nerve to the various parts of the ear. The nerve bifur- 
cates within the skull, and the anterior branch supplies the sacculus, the 
utriculus, and the two anterior ampulle. The posterior branch runs to 
the three parts of the cochlea and to the posterior ampulla. On the right 
the two perilymphatic canals are seen. Besides the parts mentioned the 
section cuts the centre of the eye and of the cerebral hemispheres, the lower 
part of the optic lobes, the nose, and the Gasserian ganglion. (x 8.) 
Fig. 19.—Diagrammatic transverse section through the posterior part of 
an adult frog’s ear, to show the course of the perilymphatic canals. In this 
figure the whole of the pectoral arch is shown, along with the head of the 
humerus. The posterior part of the stapes appears, as do the posterior 
vertical and the horizontal canal (cut twice), the posterior ampulla, and the 
two parts of the cochlea concerned. The brain is cut through the anterior 
part of the medulla oblongata, and the choroid plexus is shown. (x 8.) 
