RETINAL REFLEXES OF NARCOTIZED ANIMALS. 223 



Phenol (i 12000) was tested on a larger specimen weighing 140 

 grams. The " darkness " response was first noted after five min- 

 utes. After 1 8 minutes the "light" response was present, and 

 the " darkness " response was much more marked. A second im- 

 mediate " light " response produced a much greater reaction. The 

 animal was by no means narcotized at this stage, tapping and 

 touching still yielding marked responses. After 45 minutes the 

 " darkness " response was still noticeable, but at the end of 70 

 minutes scarcely any responses were obtainable. The animal was 

 removed to fresh sea-water, but did not recover. 



Camphor (i : 16000) was tested on a crab weighing 96 grams. 

 The " darkness " response was just observable after 22 minutes. 

 After 50 minutes " light " produced a response, " darkness " a 

 much more marked one. After 77 minutes the animal remained 

 on its back. It reacted strongly to both " light " and " darkness." 

 The reaction was still evident after four hours and the animal was 

 then by no means completely narcotized. After seven and one 

 half hours only feeble responses were given and the animal was 

 evidently moribund. 



Menthol (saturated solution) was tested on a crab weighing 75 

 grams. The animal became very active immediately after immer- 

 sion. ' Darkness " produced a slight response after three minutes. 

 After 10 minutes the reaction was very evident, but only with dis- 

 tinct pauses between each test. It continued, with gradual lessen- 

 ing, for three hours. No definite " light " response could be elic- 

 ited. The animal appeared normal throughout with the exception 

 of this response. 



(D) Calianassa californicnsis. A large burrowing sand-shrimp 

 found at low tide at Lock Bay on Gabriola Island, about three 

 miles from the station. 



Benzene (1:1500) produced a marked effect in 20 minutes. 

 The shrimps remained on their backs with only occasional tail- 

 twitches. After 45 minutes' immersion they were removed to 

 fresh sea-water. They slowly recovered. During this period 

 " light " produced definite tail movements. " Darkness " did not 

 produce a definite effect. 



Phenol (1:2000) produced complete narcosis in 17 minutes. 

 The animals were transferred to fresh sea-water. Neither during 



