226 ME. J. W. HULKE ON THE CHAMELEON'S RETINA. 



process pass inwards from these large multiangular cells into the granular layer, and 

 here break up into very fine parallel fibres, which I have traced nearly to the ganglionic 

 layer, and believe to be continuous with processes from the cells of this layer. On the 

 outer side the cells are connected with the oblique fibres. 



These fibres (figs. 7, 8, 9, 10, & 11) are directed obliquely from the outer to the inner 

 surface of the layer, and from the centre towards the periphery of the retina. Their 

 obliquity diminishes towards the inner surface of the layer, where many of them are 

 nearly horizontal. In the outer part of the layer they are very fine and numerous, 

 in the middle they are thicker and fewer, while in the inner third their numbers still 

 further decrease, and they become stouter and flatter. This results from the union of 

 the primitive fibres in bundles, which have an open plexiform arrangement. In the thin 

 periphery of the retina the whole course of the fibres is more horizontal. 



The following are the relations of the oblique fibres and the other tissues. The finest 

 fibres in the outer part of the layer are continuous through the intergranule-layer with 

 the primitive fibres of the cone-fibre plexus, as I have already mentioned in describing 

 this ; they also take up the smaller round and roundly oval inner granules. Combining 

 as they pass through the layer, becoming stouter and more horizontal, they join the large 

 ganglion-cell-like cells which lie near the inner surface of the layer, and the pale band- 

 like fibres which these cells send into the granular layer may be regarded as their further 

 continuations. 



5. The Granular Layer. — Around the fovea the thickness of this layer nearly equals 

 that of the inner granules ; from this point it very gradually decreases towards the peri- 

 phery of the retina. Its minute structure is a close and intricate web of exceedingly 

 fine soft filaments. It is marked by horizontal parallel bands, which appear to result 

 from a longitudinal disposition of the filaments. 



Two sets of vertical fibres are distinguishable in it. The first are connective fibres 

 passing outwards from the membrana limitans interna ; they are finer near the centre 

 than at the periphery of the retina. They divide at acute angles, and give off fine lateral 

 branches which are lost in the proper tissue of the layer. 



The second set consists of the fibres which pass inwards from the large multipolar inner 

 granules (which I look upon as ganglion-cells), and of those passing outwards from the 

 cells of the ganglionic layer. I have already said that I believe these fibres are con- 

 tinuous. 1 have occasionally seen large ganglionic cells in vacuoles in the middle of 

 this layer, at a distance from the inner granules and ganglionic layer. 



6. The Ganglionic Layer. — The cells of this layer are distinctly multipolar (fig. 12). 

 They have a faint single outline, a soft, finely granulated texture, and a very conspicuous 

 large circular nucleus. On the one side they send off the fibres mentioned in the 

 account of the granular layer, while on the other they send fibres, which cannot be 

 distinguished from nerve-fibres, to the plexiform expansion of the optic nerve. Around 

 the fovea they lie four or five deep ; their numbers increase for about 5" from this in a 

 peripheral direction, and then decrease. 



