46(3 H. M. BERNARD. 



of the rods. A portion of this refractive matter exudes 

 through the transverse membrane^ where it mixes with the 

 staining matter of the inner limb, and forms the body infe- 

 licitously termed the ellipsoid. 



(To be continued.) 



EXPLANATION OF PLATES 30 and 31, 



Illustrating Part II of Mr. H. M. Bernard's " Studies in 

 the Retina : Rods and Cones in the Frog and in some 

 other Amphibia." 



PLATE 30. 



Pig. 1. — The basal portions of two rods (newt) with remains of ellipsoids, 

 and sliowing the relations of inner and outer limb as two vesicles separated 

 by a tliin membrane. 



Tig. 2. — Part of an adult rod (toad) distorted, and showing its sac-like 

 character, the contents having ruptured down the middle. Cf. Max SchuUze's 

 rig., ' A. M. A.,' iii, pi. xiii, fig. I8cl (Pike). 



Tig. 3. — a, b. Two surface views of rods (frog, riemming), showing the 

 dotted appearance of tlie longitudinal striation. b. With a pigment granule 

 to show relative size of dots. 



Fig. 4. — a. Rod of young salamander (boiling corrosive sublimate), showing 

 the longitudinal striation straggling irregularly, b. Cross-section of a rod of 

 same eye, showing a simple reticulum attached to the dots in the walls, 



Pigs. 5 and 6. — Parts of rods and cross-sections from retina of frog (exposed 

 to osmic vapour) ; in Pig. 6, «, the rod was abnormally stretched. 



Pig. 7. — a, b. Two cross-sections of rods (frog) according to Hensen, a. 

 " Optical section of a fresh rod." b, " Optical section of a rod fixed with 

 osmic acid." 



Pig. 8. — A cross-section of the same according to Max Schultze. 



Pig. 9. — Part of a rod («), with cross-section {h), and a small piece cut off 

 tangentially {6) from retina of axololl; note the density of reticulum near the 

 tip of the rod. Cf. b with Hensen's section, Pig. 7, a. 



Fig. 10. — Upper portion of rod of same (Perenyi), partly in optical section, 

 showing part of nucleus and inner limb ; the reticulum of the latter can be 

 seen (1) coming from the nucleus, (2) condensing on what is called the ellip- 



