206 



BULLETIN OF THE 



EXPLANATION OF FIGURES. 



ABBREVIATIONS. 



cell. 



\11 the figures were drawn with the aid of an Abbe' camera. Except where 

 otherwise specified, all the preparations were examined in benzol-balsam. 



Figures 1 to 18 represent the structure of the median eyes. Figures 1 to 9 

 illustrate the adult eye. 



PLATE I. 



Fig. 1. A horizontal section of the retinas of the two median eyes seen from the 

 dorsal side. The tissue has been simply hardened and cut, the pigment 

 remaining intact, and no dye being employed. X 195. 



Fig. 2. A transverse section of the retina r>^ the right median eye seen from the 

 posterior face. The pigment has been removed by potassic hydrate 

 and the tissue stained in Grenacher's alcoholic borax-carmine X 195. 



PLATE II. 



Fig. 3. The outer face of a frontal section through the retina of a median eye. 

 The portion of the figure nearer the right side is close to the centre of 

 the retina, that to the left is nearer the periphery. Colored with Klei- 



