468 H. M. BERNARD. 



Fig. 20. — Frog (Flemming) ; a nucleus iu position of cone-nuclei, but con- 

 deuseil, with a vacuole near it and apparently discharged from it. 



Fig. 21. — Frog (Flemming); two nuclei passing, with amoeboid changes of 

 shape, through the outer reticular layer. 



Fig. 22. — Axolotl, showing the similarity of the cone-nuclei to those of 

 middle nuclear layer. 



PLATE 31. 



Fig. 23. — The same, showing a nucleus passing through the outer reticular 

 layer; a double cone, one with condensed and the otiier with vesicular 

 nucleus (cf. Fig. 18, right-hand nuclei). 



Fig. 24. — The same, showing a spot where one nucleus, or perhaps two 

 nuclei, have passed outwards, and apparently dragged the tissue outwards 

 with tbem and left a large gap in the middle nuclear layer. 



Fig. 25. — Salamander (Perenyi), showing three nuclei, two working out- 

 wards through the outer reticular layer. 



Fig. 26. — Frog (Flemming) ; a nucleus passing through the outer reticular 

 layer, preceded by a fluid space and an exquisitely fine staining network. 



Fig. 27. — Axolotl (Perenyi) ; a large nucleus with a similar fine staining 

 network above it, and the reticulum condensing at the distal end of its inner 

 limb ; on tiie right is a small condensed rod-nucleus, with the reticulum of 

 the inner limb condensing on the ellipsoid (cf. also Figs. 10 and 23). 



Fig. 28. — Frog (Flemming), showing upper end of a cone with a reticulum 

 traversing the basal vacuole. 



Fig. 29. — o,^, a series of figures from the retina of a young salamander 

 (seven weeks old, Perenyi), showing in developing cones and in rods the 

 origin of the staining reticulum of outer limbs from that of the inner limbs, 

 and sometimes from bright round masses of chromatin. The connection of 

 the reticulum with that of the nucleus is shown in a, i,j (cf. c, d, e,f, g, with 

 Fig. 15, a). 



Fig. 30. — Two rods from the retina of the newt. The very delicate longi- 

 tudinal striation of the outer limbs is shown, and in connection with the outer- 

 most rim of the coarsely granular ellipsoid. Above the ellipsoid is a fluid 

 vesicle very variously developed, but not infrequently slightly flattened (Max 

 Schultze's " biconvex lens "). Fluid vesicles or vacuoles are also very com- 

 monly seen iu the nuclei and in the axes of the rods. 



