13 



inHuoiu'cd. Giltiiy also l)rt)u*>lit forward very satisfactory ovidonco 

 of the iiiinicdiatc otl'ect of forei*jfii pollen on the color of the kernels 

 of rj'c, in which case the color caused by xenia was found to he in 

 the aleurono layer of the endosjierui. 



A phenonien<Mi <|uite similar to xenia in its results, thouiili prohably 

 due to verv ditierent causes, occasionally occurs in the animal kin<jf- 

 dom. In a review of Professor Ewart's Penycuik Kxperiments, in 

 Popular Science Monthly/ it is stated that "A hen which has been 

 crossed with a cock of another breed often lays eggs whose shell is no 

 longer like that of its own breed, but in color, and frequently in 

 texture, resembles that of the breed with which it has i)een crossed." 

 When we recall that the shell is deposited by a special shell gland 

 which is in no way connected w ith the ovary, but is a j)art of the quite 

 distinct oviduct, and that the change in the color of the eo-oshell 

 nuist be caused l)y some change In'ought about in this gland ))y the 

 cross fertilization, we see that in some ways the phenomenon closely 

 resembles that of xenia in plants. 



METHODS AND RACES USED. 



The experiments on which this article is based were conducted in 

 Washington, D. C, and at the Ne})raska Agricultural Experiment 

 Station. In 1898, plants of Hickory King, Oilman Flint, Learning 

 Yellow, and Peruvian, or Cuzco, were grown in the greenhouse at 

 Washington for the purpose of crossing the tirst three with the Cuzco. 

 The seed of the latter was imported from Peru, and being a subtropical 

 race, was grown in the greenhouse because the season at Washington 

 is not long enough to permit the plants to mature. Ears of each of 

 the varieties used in these experiments were also inbred to determine 

 whether they were true to seed. In the summer of 1899 the hybrids 

 obtained in 1898, together with inbred ears of the other varieties 

 grown that season, and twelve other sorts, Avere grown under the 

 writer's direction at the Nebraska Experiment Station. In the experi- 

 ments described below the crosses made in 1898 are so indicated and 

 the resulting hybrids grown in 1899 are described. The majority of 

 the experiments were made in 1899, however, and in these cases no 

 statement is made as to when and where the cross was made. , In these 

 instances it is to be understood that the crosses were made with plants 

 grown at Lincoln, Nebr., in the summer of 1899. 



The work done at Lincoln was in cooperation with the Agricultural 

 Experiment Station, and the writer is greatly indebted to Professor 

 Emerson, Mr. Benedict, and others at that institution for their kindness 

 in furnishing facilities for the work and for aid in the course of the 

 experiments. In all the crossing and inbreeding experiments very 

 careful methods were used. The ears operated upon were inclosed in 



1 Vol. 57, p. 134. June, 1900. 



