224 A ' T ' CAMERON AND C. H. O DONOGHUE. 



narcosis nor during recovery were any " light " or " darkness " 

 reactions observable. 



Camphor (i: 16000) produced no effects. After four hours' 

 immersion the animals were quite normal. 



() Spirontocaris paludicola. A small shrimp found amongst 

 the eel-grass at low tide. 



Camphor (resublimed, 1 : 16000) produced narcosis in 12 min- 

 utes. The animals did not curl up. Transferred to sea-water, 

 they slowly recovered. During this period a " light " reaction was 

 doubtfully present. No " darkness " reaction was observed. A 

 somewhat larger specimen was narcotized within one minute. 

 During recovery after transference to fresh sea-water similar 

 doubtful effects were obtained. 



(F) Hippolyte calif orniensis. Small shrimps found amongst 

 eel-grass. 



Benzene (1:1500) caused at first activity. The animals be- 

 came sluggish and showed some tendency to cling together in chains 

 (apparently a similar effect to that observed by Frohlich and 

 Kreidl with prawns in camphor). During this period no " light " 

 and " darkness " responses were observed. After 20 minutes the 

 animals were transferred to fresh sea-water. Within two or three 

 minutes " light " produced a definite response, and " darkness " a 

 much more marked one. These consisted of slight twitches 

 throughout the body of the animal, jerks of antennae and legs 

 sometimes sufficient to move the animal its own length from its 

 original position. Tapping or touching the animal at this period 

 produced no effect. A second experiment with (i : 2000) benzene 

 produced almost complete narcosis in 14 minutes, and, after trans- 

 ference to fresh sea-water, positive " light " and " darkness " re- 

 sponses in four minutes. 



Phenol (1:2000 and 1:4000) was fatal within one minute. 

 Phenol (1:10000) was fatal in two or three minutes. No re- 

 sponses to " light " or " darkness " were observed. 



Camphor (resublimed, i : 16000) produced a marked action. At 

 first the animals gave marked springs, then curled up. During 

 this period " light " and " darkness " reactions were absent. After 

 four or five minutes the animals were transferred to sea-water. 

 They immediately commenced to relax. Several gave distinct re- 



