HISTOLOGICAL ELEMENTS RETINA NECTURUS  — 427 
fibers per unit area occurred, but not sufficiently great to call 
for more than passing notice. In table 12 I have given the aver- 
age numbers of fibers per unit area and the average numbers 
for five retinas in each of the selected regions. The fibers were 
counted in unit areas, in some cases in right and left eyes of the 
same animal, and in others in two regions in the same eye; but 
I could detect no characteristic differences. In table 13 the 
average number of fibers in five unit areas is given as 97.5 and 
the total number in the whole retina is between 21,729 and 32,672. 
e. Inner nuclear layer. The inner nuclear layer presents in 
Necturus a variable condition, which makes it, of all the retinal 
layers, the most ‘difficult in which to count the nuclei. It con- 
TABLE 12 
Number of Miiller’s fibers per unit area of 0.0078 sq. mm. 
10 HE EYEBALL IN WHICH THE UNI EA 
eNO REGIONS OF T Y H T AREAS WERE LOCATED 
EYEBALLS Saal 
Anterior | Posterior } Dorsal Ventral 
| 5 
| Fundus ; 
Tr | | | oT 
21 
21 r gs wees | | 
Di | 17 hee ol 
28 r | 15 
31 1 19 
40 r 18 | 
Averages of 5 
retinas 19.1 20.9 18.0 PALS 18.2 
™ right eye; iE left eye. 
