FISHES 



325 



from the upper (aerial) pupil and its long axis refracting rays from the 

 lower (aquatic) pupil onto the upjjer part (Fig. 385). It would seem 

 therefore that both aerial and aquatic objects are focused simul- 

 taneously on different j^arts of the retina, the dioptrics in either case 



Figs. 382 to 3S-J-. — Axablfps TETnoriiTHALiiv>!. 



Fir;, 



i'l' 



5i. 



Showing the horizontal division of the pupil, the upper part being adapted 

 for vision in the air, the lower part in the water. A Brazilian specimen 

 (N. Ambache). 



being catered for by the peculiar shape of the lens (Fig. 766). The 

 four-eyed blenny. Dialoymnns fuscus, which frequents rocks between 

 the tide-marks, has a similar division of its otherwise heavily pigmented 

 cornea into two clear areas, but the pupillary aperture is single (Breder 

 and Gresser. 1939). A pupil which is practically double, however, is 

 seen in the large serpent eel of New Zealand. Leptognathus. an inhabitant 

 of the deep seas which burrows in the mud (Prince, 1949) (Fig. 340). 



