6g8 HANDBOOK OF PHYSIOLOGY ^ NEUROPHYSIOLOGY I 



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FIG. 4. Elcctroretinograms from various types of retinas. A. Cone retina of the cold blooded 

 horned toad, Phyronosoma, showing a large diphasic (/-wave. [From Chaffee & Sutcliffe (33).] B. 

 Mammalian cone retina of the squirrel, Sciurus carolinensis leucotis, with marked a-wave and narrow 

 pointed b- and (/-waves (calibration: 0.5 mv; time, i sec). [From Arden & Tansley (8)] C. Cat 

 eye, dark-adapted, exposed to two flash durations at an intensity of about 700 meter-candles; 

 (!-wave is just visible, A-wave shows fast oscillation, followed by a drop below base line before the 

 c-vjavc begins; (/-wave or off -effect appears as a retarding of fall of response at cessation of illumi- 

 nation. [From Granit (73).] D. Guinea pig eye, dark-adapted, exposed to light intensity of about 

 goo lux, showing a definite (j-wave and indication of double ft-wave; in this eye the c-wave or sec- 

 ondary rise tends to be the most prominent phase of the response. [From Granit (73).] E. Gecko 

 eye illuminated with an intensity of 1J50 meter -candles; the first record represents 3.8 sec. illumi- 

 nation after i min. in the dark, the second record 2.8 sec. illumination after 2 min. in the dark 

 (time marks 0.2 sec. apart). [From Dodt & Heck (47).] In records, A to E illumination periods 

 are indicated by shift in the signal line. 



