126 



FREDERICK TILNEY AND LUTHER F. WARREN 



early workers. These researches include those of Beraneck 

 ('87) 21 in Anguis and Lacerta; Francotte ('87) m in Anguis; 

 McKay ('88) 255 in Grammatophora and Hinulia; Strahl and 

 Martin ('88) 383 in Lacerta, and Ritter ('91) 332 in Phrynosoma. 

 There is a general agreement regarding the histological structure 

 of the retina among saurians, and the following layers have 

 been identified by most of the investigators mentioned : 



' 



Fig. 65 The structure of the retina in the pineal eye in Sphenodon punctatum. 

 according to Spencer, 1886. 



1. An inner layer of long, cylindrical cells, called the rods or 

 rod-like bodies of Spencer 366 or the cellules batonnets of Fran- 

 cotte. 127 In these cells pigment occurs. 



2. An inner layer of cells, called the 'couche cellulaire interne' 

 by Francotte. 127 This consists of round cells with a large round 

 nuclei. Ritter 332 distinguishes two types of nuclei in this layer, 

 namely, those which are round and small and those which are 

 oval and long. 



