480 SLONAKER. [Vol. XIII. 



Kingfisher (Ceryle alcyon). 

 The same conditions exist as are found in the hawk (PI. 

 XXIX, Figs. 44, 45)- 



White-Bellied Swallow (Tachycineta bicolor). 



A fovea nasalis and a fovea temporalis are easily seen, each 

 surrounded by a round area situated on a band-like area extend- 

 ing obliquely across the retina. The positions of the foveae 

 are very similar to those described in the hawks. The fovea 

 and area temporalis are likewise smaller, and are situated nearer 

 the ora serrata than the fovea and area nasalis in the hawks. 

 The area and fovea nasalis are shown in PL XXIX, Fig. 46. 



Common Tern (Sterna hirundo). 



In this case both nasal and temporal foveae surrounded by 

 round areas are present, and in addition a band-like area. The 

 area nasalis is located on the band-like area about the center of 

 the retina, but the area temporalis is above the band-like area, 

 and apparently in no way connected with it. A dark line, 

 resembling a trough-like depression, extends through the center 

 of the band-like area, through the fovea nasalis, and terminates 

 near the entrance of the optic nerve (PI. XXVII, Fig. 12). A 

 cross section of this area, given in PI. XXIX, Figs. 40, 42, 

 fails to demonstrate such a depression. The temporal end of 

 the band-like area widens and soon becomes indistinct. The 

 fovea temporalis is very shallow and might be overlooked. It 

 is located near the ora serrata a little above the median hori- 

 zontal plane. The fovea nasalis is deep and easily observed 

 (PI. XXIX, Figs. 41, 43)- 



Reptiles. 



In the tabulation twenty-five species are mentioned. All but 

 three are described as having an area, and these three are ques- 

 tionable. Eight of the number possess a well-defined fovea, 

 while two are doubtful. 



In snakes an area seems to be the rule. In the three 

 species I have examined, the retina was not suflficiently well 



