PROPAGATION 



65 



quiescent intervals last a few seconds and the circling move- 

 ments are then resumed." 



"At 1.30 (i.e., in one hour) egg laying begins. During 

 the emission of eggs the two fish lie side by side on the bot- 

 tom. The female is turned partly on her side so that her 

 median plane forms an angle of about 45 degrees with the 

 plane of the horizon. The male remains upright with his 

 head just back of the pectoral of the female or opposite it. 

 While emitting the eggs 

 the female moves her 

 pectorals alternately and 

 slowly back and forth like 

 oars ; at the same time her 

 dorsal is partly depressed 

 and rapidly vibrated. 

 During this time the male 

 lies quiet at the side of the 

 female, but toward the 

 close of the egg laying 

 interval he backs slowly 

 with alternating move- 

 ments of his pectorals until 

 his snout is opposite her 

 vent. He then usually 

 bites her on the vent, ap- 

 pears to examine the emit- 

 ted eggs and then moves forward and bites her once or 

 twice on the opercle or cheek. Four successive egg laying 

 periods timed with the watch are found to be 4 sec.; 4.5 

 sec.; 5.5 sec.; 6 sec." 



"Each egg laying period is succeeded by an interval of 

 circling over the nest or just at its edge, but the two fish 

 are now less active. The female especially is more quiet, 

 and no longer rubs her belly on the pebbles. The male 

 moves about somewhat, but less actively than before egg 



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