154 



LESLIE B. AREY 



(2) Abramis. The cones, with their large oval eUipsoids 

 10 M in length, are very conspicuous in stained preparations. 

 The fine rods, on the contrary, are not always, demonstrable 

 when treated with the Ehrlich-Biondi stain, which acts in an 

 unusually capricious fashion in respect to these elements. 



The elongated cone cells are more or less uniformly extended, 

 although the variabiHty in length is greater under these con- 

 ditions than when in the retracted state. The rods, however, 

 are arranged in the dark at very irregular levels so that retinas 

 present a fairly even distribution of them from 8 ^ to sometimes 

 as far as 50 ^ from the external limiting membrane. In the light 

 the condition is one of more uniform elongation. 



In tables 3, 4, and 5, are presented the data obtained from 

 measurements at 5°, 15°, and 25°C. in the dark. 



Measurements from the retinas of four Abramis which had been kept at 5°C. in the 

 dark; the values are in micra and represent measurements taken along axes coin- 

 ciding with radii of the eyeball 



TABLE 4 



Measurements from the retinas of three Abramis which had been kept at 15°C. in the 

 dark; the values are in micra and represent measurements taken along axes coin- 

 ciding with radii of the eyeball 



