112 W. J. DAKIN. 



Fig. 10. — Transverse section of cornea and subcorneal tissue of 

 P. Jacob ajTis (Bielschowsky-Paton method). X 650. 



Fig. 11. — Isolated cells from distal surface of lens. P. maximus, 

 chromic acid maceration. X 330. 



Fig. 12. — Transverse section of cornea and pigment-mantle of 

 P. tigrinus. Fixed Zenker, stained Mallory. X 300. 



Fig. 13. — Schematic view of retinal elements, reconstructed from 

 sections and macerations. The two left-hand rod-cells are shown in 

 external view, from macerations, and the two right-hand ones in section. 

 X about 920. 

 Fig. 13a. — Distal ends of two rod-cells (chromic acid maceration). 

 Fig. 14. — Rod-cells with i^artly broken-up rods, showing the bristle- 

 like appearance of axial fibre. P . m a x i m u s (chromic acid maceration) . 

 X 900. 



Fio-. 15. — Isolated interstitial supporting cells from retina ; a and h 

 are two outer interstitial cells. P. maximus. Chromic acid and 

 chloral hydrate macerations. X 900. 



j^jcp. 16. — Transverse section of distal sense-cells and outer inter- 

 stitial cells. Mallory's connective-tissue stain. P. maximus. X 940. 

 Fig. 17. — Transverse section of rods and rod-matrix. P. jacobaeus. 

 Fixed Zenker, stained by modified Weigei-t method. X 800. 



Fig. 18. — Distal branch of optic nerve, breaking up into branches on 

 sin-face of septvmi. P.jacobseiis. From teased preparations. X 250. 

 Fio-. 19. — Tapetum in surface view. From sections. The large circle 

 shows relative size of a rod-cell in section, x 1600. 



