514 THE AMERICAN NATURALIST [Vol. XL V 



surface of the seed, but has a characteristic notch at the 

 micropylar end (lower end in the figure). In e the area 

 has extended over the micropylar end of the seed. In 

 this form and the next there are usually some isolated 

 spots of pigment in the non-pigmented area. In / the 

 pigmented area covers all except the dorsal portion of 

 the chalazal end of the seed. Between the forms a and 

 / there is nearly a complete series of connecting links 

 represented in the material in my possession, but in the 

 present paper I shall not attempt to deal with this whole 

 series, because the genetic relation between some of its 

 members is not yet worked out. Forms a-c will here be 

 considered as one, under the name ordinary eye or small 

 eye. Forms e and / will be treated as one, under the 

 name Holstein, from the color pattern of a variety hav- 

 ing this name. The evidence thus far available indi- 

 cates that form d, which is here called large eye, is al- 

 ways heterozygous between Holstein and small eye. 

 Perhaps other of these forms of eye are also hetero- 

 zygous; material which it is hoped to obtain from the 

 crop of 1911 (F 8 ) will probably determine this point. 

 There is some evidence that forms a, b and c are the 

 DD, DR and RR of a MendeHan pair. The same is prob- 

 ably true of e and / and a type intermediate between 

 them. Form g of Fig. 1 represents a genetically dis- 

 tinct type of eye. In it the pigmented area surrounds 

 the hilum, but the micropylar end of the area has the 

 margin very indistinct ; fine dots of pigment extend over 

 the micropylar end of the seed. In races of this type 

 that are black pigmented the pigment extends over the 

 whole surface of the seed, but it is much denser in the 

 region of the eye than elsewhere. The reduced pigmen- 

 tation in such cases varies from very dark, rendering 

 close inspection necessary to detect the eye, to very pale, 

 making the eye as conspicuous as it is in buff or red pig- 

 mented races. Whether these variations in intensity of 

 pigmentation have genetic significance is not yet deter- 

 mined, but investigations now in progress will, it is 

 hoped, settle this point. This type of eye, in which an 

 ill-defined area of pigment extends over the micropylar 



