238 Studies in the Phusiolofjjf of Fertilization, 



different lots of eggs, iiiid dtlicr tests of their cross-fertilizing capacities. 

 For the former, sperm was removed from the sperm duct of the same 

 animal from which the eggs were derived, and a suspension of it made 

 up. Approximately equal quantities of the different lots of eggs were 

 put into di.shes containing 10 cc. of water, and to each 1 cc. of a thick 

 " own " sperm-suspension was added. For the cross-fertilizations a 

 dilute spcrm-susi)ension of another individual was made up. Fifty drops 

 of this were added to each of a number of dishes containing approxi- 

 mately equal amounts of the different lots of eggs in 10 cc. water. The 

 results of the experiments are shown in Table VI. 



TABLE VI. (7.6.1 and 8.11.1.) 



Vart of oviduct from wliich eggs were taken 



Base Middle To|j 



( J eggs selfed, Aja 4 — 12 



( .-1 eggs crossed, Ajh lUO — 100 



\ C eggs selfed, Cjc i 1 — 



( C eggs crossed, Cjd 100 lUO — 



E eggs selfed, Kje 9.i 90 — 



E eggs crossed, £.'/.' 5 20 — 



Exp. 4. G eggs selfed, (ijg 89 85 — 



Exp. 1. 

 Exp. 2. 

 Exp. 3. 



Part of oviduct from which eggs were taken 



Exp. 



Lower Upper 



Base middle mituile Top 



\ H eggs selfed, ///7i 



^ K eggs crossed, Hji 00 IS 17 1 



The Table shows at a glance that there is no uniformity in the self- 

 fertilization percentages of eggs taken from the base and from the top 

 of an oviduct of a given animal. Nor do the different animals agree in 

 the eggs from the top being always either more or less readily self- 

 fertilizable than those from the base. Exps. 3 and 5 show that the 

 same conclusions apply to the cros.s-fertilization percentages (in Exps. 1 

 and 2 an excess of sperm was present and no comparisons are possible). 

 Finally there is no correspondence between the self-fertilization per- 

 centages of eggs of a given animal, taken from the base and from the 

 top of the duct, and the cross-fertilization percentages of these eggs. 

 In Exp. 8 eggs from the base were more readily self-fertilizable than 

 those from the top, while the reverse held fir the cross-fertilizing 

 capacitii'S. 



Besides the above, further experiments were laadu in which, not 

 only the eggs were removed separately from the different regions of the 



