lyS FUNCTIONS OF THE BRAIN. 



II. Abdomino-thoracic. — August 14. a. Hand placed on right side of abdomen causes 

 raising of the abdomen and flexing of left legs. Hand placed on left margin of abdomen, no 

 result; or if the fingers cover considerable area, a slight raising of abdomen may be produced. 



h. August 25. Crab is vigorous. Hand, or even the tip of a finger, placed lightiy on the 

 right margin of the abdomen causes raising of the left legs, followed shortly afterward by the 

 right, and then by general movements of both sides. Hand placed on the left margin of the 

 abdomen, and on the left gills, produces at first no effect; but if the stimulus is increased, then 

 the left legs are raised, followed by general movements, including movements of the right 

 legs. Experiment repeated many times, with same results. 



III. Gustatory Reflexes. — a. August 7. Stimulation of jaws caused normal chewing 

 movements on either side, but movements of one side do not harmonize with those of the other. 

 b. August 25. Same. 



IV. Respiratory Reflexes. — August 24. a. When at rest, the left abdominal appendages 

 are more elevated than the right. 



b. Stimulation of the gill warts with clam causes twitching of the stimulated endopodites, 

 then several lateral movements, the members of each pair stimulated alternately crossing and 

 uncrossing over the median line, and finally a full, rhythmical, up and down, respiratory move- 

 ment of all the abdominal appendages. 



Experiment II — B. 



August 25. Cut both crura back of the cheiicerse. Subsequent examination showed that 

 the cut was made in front of the second neuromere on the left, and behind it on the right. 

 (Fig. 113, B.II.) General movements of the legs and respiratory movements of the gills 

 followed, but they lasted only a short time. 



I. Gustatory Reflexes. — a. Immediately after operation, washed away the blood and 

 stimulated the jaws with clam, producing marked leg movement, as in chewing, but very feeble 

 jaw movement, b. Repeated the experiment after five minutes with same results, c. Again, 

 two days later, stimulation of jaws with food produces chewing reflexes, consisting of leg move- 

 ment only on the left; on the right, no reflexes. 



II. Respiration. — a. On removing the crab from the water, all the left gills pulsate a few 

 times, the right remain motionless. 



b. When returned to the water after long exposure to the air, the respiration becomes nearly 

 normal. The left legs are very restless and move back and forth in a lateral direction. The 

 right legs are relaxed and motionless, except the sixth, which is directed backward and moving 

 slightly. 



c. Respiratory movements may now be induced by rubbing the gills with clam. The same 

 premonitory twitching and lateral movements as in experiment 1. Repeated frequently with 

 same results. When the movements are well under way, the left gills are raised higher than the 

 right. 



III. Purposeful Movements of Sixth Leg. — When the fingers were placed on the left 

 abdominal appendages, the left, sixth leg was thrust repeatedly backward over the median sur 

 faces of the gills, with the very evident purpose of thrusting away the stimulating object. The 

 other appendages moved very slightly, but did not in any way make purposeful movements 

 on stimulation of thorax. 



Experiment III — A. 



July 29 Female. Cut the nerves to the endopodites of all the left abdominal appendages 

 about half way up the appendages. No other effects were observed than the loss of sensibility 

 of the left abdominal endopodites. 



