274 Notes on the Pigmentation of the Human Iris 
2. The buff or yellowish tinting being confined to the upper parts of the 
irides in two members (I. 2 and II. 1), and pigment being rather more dense in the 
same regions in II. 3. 
3. The appearance of pupillary circles in II. 4, while they are absent in the 
parents. 
B. Family: 
This pedigree is interesting : 
1. From the mating of blue, almost free from visible anterior pigment, with 
very rare and peculiar dense grey, almost white, irides free from visible anterior 
pigment. 
2. From the occurrence of the same peculiar white or light grey irides in 
three of the children, viz. II. 1, 2, 3. 
3. From the appearance of pigmeut circles in four of the five children, the 
parents being free from them. 
4. From the buff staining occurring in the upper parts of the irides of I. 1. 
5. From the blue peripheral zones of II. 2. This appearance may partly be 
due to the fact that in this region the iris is thinner than elsewhere. In a clear 
yellow yellow-ammer — a clinically complete albino with pink eyes — which I have 
alive at present, this same grey colour occurs as a pupillary ring, where the iris is 
thickest, the median and peripheral zones being translucent and showing the red 
fundus reflex through them*. 
6. From the absence of photophobia and other signs of albinism. 
G. Family : 
1. The eyes of I. 1, to any ordinary observer, are blue with no visible anterior 
pigment. 
2. Mated with a blue with no visible anterior pigment, there appears the 
heterochromic iris of II. 1, showing a large deposit of anterior pigment. 
3. Neither of the parents is ringed, but two of the children are, viz. II. 2 and 3. 
D. Family: 
1. The red pupillary ring of I. 1 corresponds, as is frequently the case, with 
the original reddish colour of the hair. 
2. Red hair is more subject to change of colour, and is more closely connected 
with albinism than other colours. 
3. The two children are verging on albinism and show variation in refraction, 
II. 1 being hypermetropic, and II. 2 myopic. 
* This bird {Emberiza citrinella ? ) is now dead, and Dr Usher, who kindly examined the eyes, 
reports them to be entirely free of pigment, except in the posterior pigment epithelium of the irides, 
which is very lightly pigmented : see "Canary Breeding," Biometrika, Vol. vn. Plate II. 
