PEALE au 
All figures are from Necturus and are magnified 1,450 diameters. All 
preparations were fixed in corrosive-acetic mixture and stained in Heiden- 
hain’s iron-alum-haematoxylin. 
Fic. t1—Two rods and one cone as seen in a radial section of the 
retina. The small rod at the right shows the peripheral system of stained 
fibrils. "These are seen most distinctly at low focus; 7. e., on the lower 
surface of the rod. The sides are out of focus. Small portions of the rods 
are broken away at the distal end. (Cf. other figures.) 
The paraboloid (pa’b. bac.) of the large rod, drawn in optical section, 
is clearly eccentric, a condition not very rare. The nucleus and other parts 
are shown from a focus at the near surface. 
The cone (on the left) has an appearance typical of this material. 
‘The outer segment is much vacuolated and with only a slight general 
stain. Superficial fibrils show faintly and are slightly oblique. The fibrils 
over the paraboloid are more distinct. The paraboloid itself is out of focus. 
The heavily stained granules are characteristic of the ellipsoid 
(ell.) of the cones. 
Fic. 2—The double cones showing the marked differentiation between 
the individual elements of the couplet. In A the couplet is seen laterally; 
i. e., both cones are in the plane of section. In B the couplet lies in a 
plane at right angles to that of the section, and the far cone, only, is in 
focus. A comparison of the different views of the myoids (my. con. dst.) 
in the far cones in A and in B shows the flattening of the myoid. 
Fic. 3.—Cross section of an outer segment of a cone; the surrounding 
elements are in outline only. ‘The peripheral, stained fibrils are seen in 
section and also obliquely lengthwise; they are separated by some little 
space from the dark stained center. 
Fic. 4, A.—Cross section of a cone through the paraboloid. The 
stained fibrils occur in two concentric circles, neither of which is on the 
surface. 
Fic. 4, B.—Cross section of a rod through the paraboloid; the fibrils 
are closer to the paraboloid than to the surface. 
Fic. 5, A——Cross section of a double cone through the paraboloid of 
the near cone, and the myoid of the far cone. : 
Fic. 5, B—Cross section of the distal end of a nucleus of a rod 
showing fibrils in the surrounding cytoplasm. 
Fic. 6.—Cross section of the ellipsoid of a rod. The stained fibrils are 
superficial. The ellipsoid granules are distributed through the central 
portion. 
