146 Papers from the Marine Biological Laboratory at Tortugas. 



TABLE V. Summary of results of cross-fertilization in sea-water of decreased 



alkalinity. 



[Hydrochloric acid. Number of plutei studied in each fertilization, 50. Temperature, 2g-2g.s C.] 



Further data: 



1909. Eggs fertilized in 400 c.c. sea-water 4- 10 drops A HC1. 



(1) 1910. Eggs fertilized in 500 c.c. sea-water+ 15 drops A HC1. 3 days. 



(2) 1910. Eggs fertilized in 500 c.c. sea-water+ 15 drops A^ HC1. 4 clays. 



(3) 1910. Eggs fertilized in 500 c.c. sea-water+is drops A HC1. 5 days. 



(4) 1910. Eggs fertilized in 500 c.c. sea-water+3o drops A HC1. 2 days. 



(5) 1910. Eggs fertilized in 500 c.c. sea-water+30 drops A HC1. 2 days. 



Table VI shows that the effect of the addition of the acid has been 

 to swing the dominance in the Hipponoe 9 X Toxopneustestf cross to the 

 Toxopneustes side: 



TABLE VI. Summary of results of cross-fertilization in sea-water of decreased 



alkalinity. 



[20 drops A acetic acid to 400 c.c. sea-water. N T umber of plutei studied, 50. Temperature, 29 C.] 



