160 GEORGE L. STREETER 



ought to have. The lateral wall in reality presses directly 

 against the lateral canal. Aside from this dropsical tendency the 

 general form of the labyrinth is quite normal. There is some 

 deficiency in the cartilaginous capsule, particularly in the lateral 

 center. 



Labyrinth VI: (figures 11 and 12). Figure 11 is taken from 

 Series X 4 A, slide 7, row 1, section 4. This section passes through 

 the endolymphatic sac, crus commune, vestibule with its thickened 

 macula acustica, and the lateral canal. The endolymphatic sac 

 comes in contact with the chorioidal membrane in sections oral 

 to this. Both histologically and in its general form this labyrinth 

 is quite perfect. Figure 11 is the only photograph in the series 

 that was retouched in any way. Here the negative was scratched 

 to show the outlines of the lateral canal and lateral wall of the 

 vestibule more distinctly. 



Lahyrinth VII: (figures 13 and 14)- Figure 13 is taken from 

 Series X 7 B, slide 6, row 3, section 3. The section passes through 

 the endolymphatic sac, the crus commune, and the combined 

 vestibule and lateral canal. The lateral canal exists only as a 

 lateral pouch from the general vestibular cavity. A partial 

 separation is indicated by an indentation on its dorsal surface, 

 as can be seen in figure 14. The indentation does not completely 

 perforate the pouch, so the canal is incomplete. There seems to 

 be a general defect of the caudal portion of the labyrinth. So 

 that, in addition to the imperfect lateral canal, the lagena is 

 absent and the posterior canal small though otherwise complete. 

 The acoustic ganglion is large (figure 13) and has a well developed 

 root connecting it with the brain. The endolymphatic sac pre- 

 sents the usual relation to the chorioidal membrane. 



Lahyrinth VIII: (figures 15 and 16). The photograph shown 

 in figure 15 is taken from Series X 2 B, slide 5, row 1, section 2. 

 In the process of embedding and mounting this series, some of the 

 sections were injured, though not enough to interfere with the 

 identification of the different parts. Thus it can be plainly seen 

 that figure 15 passes through the endolymphatic appendage, the 

 crus commune, the vestibular pouch, and the lateral canal. The 

 anterior half of the labyrinth is quite perfect, as can be seen in 



