154 EDWARD L. RICE 
The examination of other stages of Eumeces throws further 
light on this point. In stage 6 the glossopharyngeus passes from 
the brain cavity (fig. 15, n.JX.) through the cartilage of the 
median wall of the otic capsule just dorsal to the median aperture 
of the recessus scalae tympani (fig. 14) into its cavity (fig. 13). 
Here there can be no question of the ‘intracapsular’ course of the 
nerve, although its final exit, as in stage 5 of Eumeces and in 
Lacerta, is through the membrane of the lateral aperture of the 
recessus, and not, as in the turtles, through the cartilage. In 
stages 2 and 3 the conditions could not be determined with 
certainty, but apparently stage 3 is like stage 6, while stage 2 
resembles stage 5. Stage 4 is unquestionably like stage 6. The 
difference is, then, not one of age, but rather due to individual 
variability, as in the case of variations in the hypoglossus and 
abducens foramina. From the available material it isimpossible 
to determine which condition (if either) is the characteristic one 
in Eumeces. This variation suggests a method by which the 
‘extracapsular’ course of the glossopharyngeus, as seen in the 
Amphibia (Gaupp, ’93, 705 b), may phylogenetically have been 
transformed into the typically ‘intracapsular’ course in the turtles 
through a gradual extension of the otic cartilage. Gaupp (05 b) 
suggests that the change has occurred through a striking narrow- 
ing of the recessus scalae tympani; I would suggest rather a 
narrowing of the fenestra cochleae. In stage 6 of Eumeces the 
cartilage of the median wall has been sufficiently extended to 
surround an inner glossopharyngeus foramen; in the turtle a 
similar lateral extension has enclosed the foramen externum. In 
this connection it is interesting to note the very small size of 
the fenestra cochleae in Emys (Kunkel, 712 b, fig. 29). A more 
detailed knowledge of the later embryonic development of this 
region and its adult anatomy is highly desirable. 
