448 H. M. BERNARD. 



evenly round the rod. I find in my notes that at times two 

 series of dots at right angles to one another are recorded as 

 marking the exterior of the rods. The dots were usually 

 slightly drawn out longitudinally. Fig. 3, a, h,^ are from 

 my earlier drawings. It was noticed that the dots appeared 

 almost as if they raised the surface of the rod, and that, 

 hence, between the rows there were slight fui-rows, but on 

 this point I have never satisfied myself ; if any farrowing 

 exists, it must be very slight. While these longitudinal rows 

 of dots on the outer limbs were clear with any well-preserved 

 retinas stained in Ehrlich's hsematoxylin, it was not till I 

 employed the iron-alum haeraatoxylin method of staining 

 that I saw any striation of the inner limbs, and then, while 

 that on the outer limbs was very strong and regular, that on 

 the inner limbs was hardly ever regulai", often indeed not 

 recognisable as a system of striae at all. Further, I then 

 found, as stated, that the two are not distinct phenomena, 

 but that the fine staining threads which run down in the 

 walls of the inner limbs are continued on to the outer limbs, 

 as Max Schultze observed : but they do not stop short, as he 

 supposed ; on the contrary, they run down the whole way, 

 swelling into small clumps of staining matter at short dis- 

 tances from one another, these clumps being the rows of dots 

 I had seen all along. 



Fig. 11 shows diagrammatically the arrangements of this 

 system of threads, while figs. 13, a—d, and 29, a, h, e — -J, are 

 from actual preparations of retinas from different Amphibia. 

 Beginning usually faint near the nucleus, and seldom as a dis- 

 tinct system, the arrangement gets more pronounced distally. 

 It may be very pronounced indeed near the ellipsoid (e. g. in 

 the toad, fig. 13, a, b). Here it passes on to the outer limbs, 

 and, where inner and outer limbs are stretched a little apart, 

 may be seen as a nearly regular ring of smooth, thin threads, 



* Cf. Max Schultze, ' Arcli. niikr. Anat.,' Bd. iii, pi. xiii, fig. 11, where 

 he shows a rod covered with " pigment granules ; " another figure occurs in 

 Bd. V, pi. xxii, fig. 17 a. The dots above referred to are quite distinct from 

 pigment granules, one of which I have drawn in fig. 3, b. 



