20 Golding Bird and Schäfer, 



specimens show nothing of the structure of these layers we are unable 

 to say how far such blending may actually occur. Both molecular 

 layers appear however still to be represented quite at the centre; and 

 this is also the case with the bipolars, which here seem exactly to 

 con-espond in number with the cones and cone fibres ^). 



The nuclei of the bipolars (inner granules) are at the fovea 

 decidedly smaller than the cone-nuclei (outer granules) and are stained 

 more darkly and uniformly; they are round or oval, and tend, especially 

 a short distance from the centre, to be placed somewhat obliquely. 

 On one point viz, the presence of inner granules at the centre of the 

 human fovea we are in disagreement with most, if not all, previous 

 observers 2). Nevertheless our specimens seem clear upon this point 

 and to judge from the figures given by Cajal of the fovea in the bird 

 and the chameleon they are also present in a similar situation in those 

 animals. 



9. As to the size and form of the ganglion-ceils and the extent 

 of the ganglion-cell layer at the fovea. 



The ganglion-cells are six or seven deep at the edge of the fovea, 

 whence they gradually diminish in number as we trace them inwards; 

 and with tliis there is a corresponding diminution in the thickness ot 

 the layer which they form. They are not however smaller at the 

 fovea than for some distance on either side of it, nor are they obli- 

 quely disposed, elliptical, bipolar cells as might be supposed from the 

 diagram given by M. Schnitze'^) and that of Schwalbe; but are ol 

 a rounded or somewhat pyriform shape; with a peripheral process 

 directed almost perpendicularly outwards towards the inner mole- 

 cular layer, within which no doubt they form stratified arborisations 



*) In the fovea of the bird and in that of the chameleon it has been shown 

 by Ramon y Cajal that the bipolars exactly correspond in number with the cone- 

 fibres, against the bases of which their peripheral processes abut each against each 

 (Op. cit.). 



^) Compare however the statement of H. Müller quoted above on p. 1. 



•*) With reference to this it is noteworthy that in the original of this diagram 

 (which is to be found in Bd. 11 of the Archiv f. mikr. Anatomie. Plate 13) the 

 ganglion-cells are correctly represented as spherical bodies. For some reason which 

 docs not appear in the text Schultze seems to have had the figure modified for the 

 article in Strieker's Histology. 



