H. M. FucHS 



239 



duct, but the sperm was treated similarly. It must be pointed out, 

 however, that comparisons between the effects of sperm from the base 

 and from the top of the vas deferens on any given lot of eggs are 

 necessarily very inexact. This is owing to the fact that it is impossible 

 to make up two different sperm-suspensions of exactly equal concentra- 

 tions, since the latter can only be judged by the eye, a comparatively 

 inaccurate method. 



In each experiment the eggs were removed separately from the 

 different regions of the oviduct. Approximately equal quantities of 

 each of the lots of eggs were fertilized (1) by equal concentrations 

 of sperm from the base of the sperm duct, (2) by equal concentrations 

 of sperm from the top of the sperm duct, (3) by equal concentrations of 

 a sperm-suspension of another individual. Besides this, equal amounts 

 of the sperm-suspensions from the base and from the top of the sperm 

 duct were tested with " foreign " eggs. See Table VII. 



TABLE VII. (12.16.1.) 



Exp. 1. Eggs A selted with sperm from base of duct, AJoi 

 Egga .-1 selfed with sperm from top of duct, Aja-^ 

 Eggs /I crossed, Ajm ... ... 



Eggs C crossed with sperm «i from base of duct ... 

 Eggs G crossed with sperm a^ from top of duct ... 



Part of oviduct from which 

 eggs were taken 



Part of oviduct from which 

 eggs were taken 



Base 



6 



U 

 97 



(87) 



Lower 

 middle 



1 







81 



(87) 



Exp. 2. Eggs B selfed witli sperm from base of duct, Bjhi 

 Eggs B selfed with sperm from top of duct, B/b.^ 

 Eggs B crossed, Bjii 



Eggs D crossed with sperm bi from base of duet 

 Eggs D crossed with sperm 62 from top of duct 



Eggs E crossed with sperm &i from base of duct . 

 Eggs E crossed with sperm 62 from top of duct 



These experiments are a further confirmation of those of Table VI 

 in showing the irregularity in behaviour of eggs from different parts of 

 an oviduct both in respect to self- and cross-fertilizing capacities — see 



' The figures in brackets are tlie number of minutes after fertilization when the 4-eell 

 division was completed. See p. 245. 



l^pper 

 middle 



<1 





 85 



(87) 



"Jl 



42 



90 

 31 



Top 

 <1 







81 



(87) 



