Chapter XII 

 RELATIONS OF REPTILIAN TO AVIAN FUNDI 



The colored illustrations of three eyegrounds 

 of reptiles are published by the aid of Mr. 

 Head and through the courtesy of Mr. Lind- 

 say Johnson. In this text are also included, 

 for purposes of comparison, two black-and- 

 white drawings of mammalian fundi. One of 

 these, the Common Hedge-Hog (Fig. 143) 



Fig. 143 



Fundus Oculi of the Common Hedgehog. 

 (After Lindsay Johnson.) 



reminds one of the Indian Cobra (Plate LXI), 

 while the fundus view (Fig. 144) of the Vir- 

 ginian Opossum suggests the background of 

 the Horned Toad (Plate LX). In other 

 words, these two reptilian fundi have more 

 marked affinities with other vertebrate classes 

 than with Birds. On the other hand, were it 

 not for the absent macular region and the 

 greater prominence of the radiant, retinal 

 nerve fibres, the ocular fundus of that noctur- 

 nal lizard, Hemidactylus turcicus (Plate LIX) 

 might be regarded as an avian form, rather 



closely related, for example, to the Kiwi 

 (Plate IV). 



A reference to the probable evolutionary 

 connection between Birds and certain sub- 

 orders of Reptiles, as indicated by their 

 ophthalmoscopic pictures, has already been 

 made. It may eventually transpire, as indi- 

 cated by this "straw" of evidence, that the 

 Geckotidce are comparatively near relatives 

 of the primitive Bird, while other lacertilian 

 suborders and the Ophidia are as far removed 

 from them as the Marsupials. 



A detailed description of the three reptilian 

 eyegrounds, represented in the Atlas by 

 colored reproductions, now follows. 



Fig. 144 



Fundus Oculi of the Virginian Opossum 

 (After Lindsay Johnson.) 



[116] 



