J. R. Learmonth 



147 



TABLE II. 



No. of ofTspring in 



each of the four 



groups 



Type of mating 



-^ (a) I X I (no example) 

 (b) I X II (3 families) 



No. of ^ 

 family I 



II III IV 



(c) I X III (no example) 



(d) I X IV (3 families) 



(e) II X II (7 families) 



(/) II X III (1 family) 

 (g) II X IV (14 families) 



9 

 18 

 28 



2 1 — 



I — — 



II — 



23 



29 



38 



2 



5 



6 



15 



26 



30 



40 



39 



4 



8 



11 



14 



16 



17 



2 — 



6 — 



4 — 



— 2 



— 1 



— 2 



— 2 



— 1 



— 2 



— 1 

 2 — 



— 2 



— 1 



— 4 



— 3 



— 3 



— 3 



No. of ofbpring in 

 each of the four 



Type of mating 

 {g) II X IV (14 families) 



(h) III X III (no example) 

 (i) ni X IV (3 families) 



(J) IV X IV (9 families) 



No. of ^ 

 family I 



19 — 



22 — 



24 — 



25 — 

 27 — 

 32 — 

 34 — 

 37 — 



groups 



II III IV 



4 — — 

 1 — — 



1 — — 



2 — — 

 2—1 

 2 — — 

 2—1 

 2 — — 



20 



21 



35 



1 



3 



7 



10 



12 



13 



31 



33 



36 



_ _ _ 2 



1 — 



(g) In this, the largest group of families, there are evidently two 

 types of mating, viz. Aabb x aabb and AAbb x aabb. In Nos. 11, 14, 

 16, 27, 34 the Group II parent was evidently heterozygous, and the 

 offspring of th^ 5 families together comprise 14 dominants and 8 reces- 

 sives where equality was to be expected. In the remaining families the 

 Group II parent may have been of the constitution AAbb. 



(i) The data are scanty but suggest that individuals of Group III 

 are more often heterozygous than those of Group II. This is in accord- 

 ance with the greater scarcity of Group III individuals in an English 

 population (cf Hirschfeld and Hirschfeld, 1919). 



(j) Here we should expect nothing but Group IV individuals. 

 A single exception in the form of a Group II individual occurred in 

 Family No. 12. Hirschfeld and Hirschfeld (1919) have recently suggested 

 that in such cases the putative fatheV is not the real father. They are 

 inclined to regard the appearance of a child belonging to Groups I, II, 

 or III from parents belonging to Group IV as a proof of illegitimacy,- 

 and point out that such occurrences may afford a valuable medico-legal 

 test. 



