248 



B. H. GRAVE. 



2d night, eggs laid by two females in quiet water, about 

 100 eggs each or one tenth maximum ; spawned at 

 ii P.M.; none laid by those in running water; one 

 male shed great cloud of spermatozoa in quiet water. 



3d night, no eggs and no spermatozoa obtained in either 

 dish. 



Remark. Spawning at this time and for several days past prac- 

 tically suppressed. 



* First Quarter, July n. 



VI. 



Experiment 6, July 12-14. 



60 Chitons collected in afternoon, Tuesday, July 12, and kept in 

 running water at supply department night July 12. 



2d night, July 13, experiment set in two dishes as usual; 

 of those in running water none spawned ; of those in 

 quiet water on laboratory table three males shed 

 spermatozoa freely before 8 P.M., and others during 

 the night ; one female spawned lightly one fourth 

 the maximum amount about 10 -P.M.; about thirty- 

 five additional eggs were spawned by one female dur- 

 ing the night. 



3d night, at 10.30 P.M. a few males shed spermatozoa 

 abundantly; one female spawned and only 40-50 

 eggs in quiet water; one female in running water 

 spawned about 30 eggs during the night. 



Remark. Spawning practically suppressed. 



VII. 

 Experiment 7, July 14-16. 



90 Chitons collected afternoon of Thursday, July 14. Placed 

 about 6 P.M. in three dishes. One left in running water. 

 Two placed in quiet water on laboratory table. 



ist night, spermatozoa in small amount shed by three 

 males before 10 P.M. in quiet water; no eggs in 

 either dish up to 11 P.M.; about 40 eggs obtained 

 from one female in quiet water during the night. 



