PLATE VIII. 



Kymograph Records of Sound-producing Swim-Bladders, 



Fig. 1. Squetague. Normal swim-bladder. Twenty-four vibrations per second 

 (rapidly revolving drum). 



Fig. 2. Squeteague. Normal s-nim-bladder. Twenty-four vibrations per second 

 (slowly revolving drum). 



Fig. 3. Squeteague. Myogram of m. sonificus. Twenty-four vibrations per 

 second. 



Fig. 4. Squeteague. Myogram of m. sonificus. 



a. S^\im-bladder normal, b. Swm-bladder collapsed. 



Fig. 5. Timing fork having one-hundred double \ibrations per second. Kymo- 

 graph drum revolving at same rate as for Figs. 1, 3, and 4. 



Fig. 6. Prionotus. Swm-bladder removed. 



Fig. 7. Prionotus. Swim-bladder removed and filled with sea-water. 



Fig. 8. Prionotus. S^\im-bladder removed. Prolonged stimulation. 



(180) 



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