322 FERNANDUS PAYNE. 



r 



far as I was able to determine, were exactly the same. How- 

 ever, this is to be expected, since the fish is a highly complex 

 organism and its internal mechanism is not the same at any two 

 times. 



To determine whether the skin is equally sensitive on all parts 

 of the body, I used a light focused to a point by means of a Zeiss 

 a * objective. With the aquarium dark, I focused this light on 

 various parts of the body. Sometimes they reacted and some- 

 times they did not, but they reacted as often with the light 

 focused on the tail as on the head, and vice versa. Later I 

 placed some fishes in a dark corner of a room and with a mirror 

 threw sunbeams on various parts of the body. In nearly every 

 case I got a definite reaction. Sometimes the fishes turned 

 around and swam in the opposite direction and sometimes darted 

 forward. Further, they reacted as often when the light was 

 thrown on the tail as on the head. Judging from these experi- 

 ments they are equally sensitive on all parts of the body. How- 

 ever, this is what we might expect since all parts of the skin are 

 exposed to like conditions. Parker ('05) concludes that the tail 

 of Ammoccetes is most sensitive to light, but he accounts for this 

 by the fact that Ammoccetes burrows head foremost into the sand. 



Eigenmann ('99) states: "Two examples [of blind fishes] kept 

 in a pail in my cellar were quietly floating, but when a lighted 

 match was held above them, the fishes at once darted to the 

 bottom and sides of the pail." This is not a common reaction. 

 I have tried the lighted match again and again and also have 

 flashed the one hundred candle power lamp above them, and in 

 no case did they dart to the sides or bottom immediately. In 

 fact, they did not react immediately when the eight hundred can- 

 dle power lamp was flashed on them. With the fishes in their 

 native habitat I have made a number of observations with the 

 one hundred candle power lamp by flashing it upon them as they 

 lay perfectly quiet in the water, and in each case it was from 10 

 to 30 seconds before any movement took place. In nearly all 

 cases the movement was either to one side or straight ahead and 

 not toward the bottom. My results are more in accord with his 

 observation on forty individuals when a lighted match " produced 

 a very general and active movement among all individuals." 



