DESCRIPTION OF PLATES 



Figures 1 to 88 were drawn with the aid of a camera lucida using a Zeiss 1.5 

 mm. apochromatic objective and a 12 X compensating ocular. This gave 

 a magnification at table level of 3400 X . The pencil drawings were then en- 

 larged to twice the original size Avith an accurate pantograph. They are repro- 

 duced two-fifths off at a magnification of 4080 X . In all cases where chromosomes 

 are believed to have divided the mates are connected with a bar except when the 

 separation appears as only a slight slit. 



Figs 1 to 80 have been drawn from material fixed in Flemming's strong solu- 

 tion. See page 217 for complexes found in material preserved in Flemming's 

 weak solution. 



PLATE 1 



EXPLANATION OF FIGURES 



Spermatogonia from three breeds of pigs 



202 



