210 BREEDING 



Table in which the zygotic formulae are written ; for 

 instance, in regard to this last point, the Table on 

 p. 209 only gives half the truth ; it only shows that a 

 representative of each of the four externally distin- 

 guishable types occurs along the top-left to bottom- 

 right diagonal ; the whole truth, as revealed by the 

 Table on p. 208, being that these four representatives 

 are the only representatives of these four forms which 

 are homozygous in respect both of colour and of 

 shape. A glance at the gametic formulae at the ends 

 of the columns and rows which intersect to form 

 these squares at once gives the reason. These are the 

 squares formed by the intersection of colunms and 

 rows with the same gametic formulae at their ends. 



Another point brought out by this Table is that 

 the zygotes lying in the squares on the diagonal 

 passing from the top right to the bottom left corner 

 of the Table, contain the four yellow rounds which 

 are heterozygous in respect both of colour and of shape. 



It will also be seen that the four kinds of zygotes 

 in a row to the right of a given gametic formula are 

 the same, and follow one another in the same order 

 (reading from above below in the column, and from 

 left to right in the row) as those in the column under 

 the same gametic formula. In the YR colunm and 

 row, the squares 1, 2, 3, 4 are the same as 1, 5, 9, 13. 

 In the YW, 5, 6, 7, 8 are the same as 2, 6, 10, 14. 

 In the GE, 9, 10, 11, 12 are the same as 3, 7, 11, 15. 

 And, lastly, in the GW, 13, 14, 15, 16 are the same as 

 4, 8, 12, 16. 



A familiarity with the simple properties of such 



