252 



B. H. GRAVE. 



2d night, two spawned one fourth maximum ; very light. 

 3d night, one female spawned about one sixth maximum. 



Remark. Spawning very light. Almost none. 



* First Quarter, August 10. 



XVI. 



Experiment 16, August 12-14. 



45 Chitons collected Friday, August 12. Placed in two dishes. 



ist night, none spawned. 



2d night, three females spawned (two one fifth maximum; 

 one one half maximum ; two in one dish and one in the 

 other) ; a fourth specimen spawned 50-100 eggs after 

 10 P.M. 



3d night, no eggs. 



Remark. Impression of light spawning activity. Spawning all 

 but suppressed during past week. Quantity of eggs not sufficient 

 for embryological studies. 



XVII. 



Experiment 17, August 15-17. 



100 Chitons collected Monday afternoon. Arrived 5 P.M. Put 

 in dishes 7.30 P.M. Four dishes, 

 ist night, no eggs. 



2d night, abundance of spermatozoa shed ; water clouded ; 

 also quantities of eggs from three to five females in 

 each dish one third to two thirds maximum. 

 3d night, August 17, two females spawned one fourth 

 maximum ; spermatozoa very abundant, but very few 

 eggs. 



Remark. Very distinct revival of spawning activity; most 

 abundant this year. 



* Full moon, August 18. 



XVIII. 



Experiment 18, August 18-20. 



50 large Chitons 'collected August 18. 



ist night, animals remained in aquarium in laboratory (not 

 discovered). 



