No. 4, February, 1922] GENETICS 265 



1729. LiPPiNCOTT, W. A. Further data on the inheritance of blue in poultry. Amer. 

 Nat. 55: 289-327. 3 pi. 1921.— The author's summary is as follows: (1) It has been shown 

 that the development of black pigment in the blue-splashed, blue and black races of the Anda- 

 lusian and Orpington breeds, and of black Langshans, depends upon the action of a dominant 

 hereditary factor P, for which they are normally homozygous. (2) The allelomorph of P 

 is p. Individuals homozygous for p are white, as in white Wyandotte and white Plymouth 

 Rock breeds. (3) The extension of black pigment to all feathers of the body, resulting, if 

 no pattern factors are present, in self-colored individuals, depends upon a dominant factor E. 

 This factor has been found in the Andalusian, Orpington, white Plymouth Rock, white 

 Wyandotte and black Langshan breeds. Some evidence is presented which indicates its 

 presence in white Leghorns. (4) The blue appearance of blue and blue-splashed Andalusians 

 and Orpingtons is due to the arrangement and restriction of black pigment, the result of a 

 dominant factor R. This factor has also been found in individuals of the white Wyandotte 

 and white Leghorn breeds, though its presence is probably not usual in these breeds. (.5) No 

 individuals of the Andalusian, Orpington, white Plymouth Rock, white Wyandotte, or black 

 Langshan breeds have been found which did not carry R, E, or both. (6) The mutual rela- 

 tions of R and E are such that they have never been found together in the same gamete. 

 This indicates that they are allelomorphic, i.e., occupy identical loci on homologous chromo- 

 somes, or, each is so closely linked to the recessive allelomorph of the other, {Re) and {rE), 

 that crossing-over rarely, if ever, occurs. (7) No evidence of crossing-over between R and 

 E has been found and the tentative conclusion must be in accord with that previously held, 

 that R and E are allelomorphs. (8) Both R and E are independent of P in their hereditary 

 behavior, though dependent upon its presence for their manifestation. (9) The cooperative 

 influence of the ovary is necessary for a full expression of R in the regions of the neck, back, 

 and saddle. (10) On the basis of the evidence presented in the body of this paper the genetic 

 formulae of the breeds and varieties employed, with respect to the factors under observation, 

 are usually as follows: Blue-splashed Andalusians and Orpingtons PP{Re) (Re); blue Anda- 

 lusians and Orpingtons PP{Re) (rE"); black Andalusians, Orpingtons, and Langshans PP{rE) 

 {rE); and white Phinouth Rocks and Wyandottes pp{rE) {rE). (11) The possibility of the 

 occurrence of factors which duplicate the somatic effects of R and E is pointed out, and the 

 relation of this possibility to the production of constant-breeding blues briefly discussed. — 

 H. G. May. 



1730. LoTSY, J. P. Grondbeginselen van oordeelkundig fokken en telen. [Principles of 

 breeding.] Mededeel. Ver. Bevord. Wetenschapp. Teelt 13: 47 p. 1921.— This is a general 

 treatise on breeding animals and plants. — /. C. Th. Uphof. 



1731. Love, H. H., and W. T. Craig. Fertile wheat-rye hybrids. Jour. Heredity 10: 

 195-207. 11 fig. and frontispiece. 1919. — From a cross of Dawson Golden Chaff wheat 

 {Triticum vulgarc) 9 and common rye (Sccale cereale) d^ 1 Fj plant was obtained, the hybrid 

 nature of which was indicated by a few tip awns, brown glumes intermediate in size but 

 keeled — more as in rye — and ciliate, and slightly pubescent peduncle. One seed was produced 

 from which an Fo plant was grown. This generation showed in many ways its rye parentage, 

 and again only 1 viable seed was produced. The F3 plant resulting was more like wheat 

 than the earlier generations, showing hybrid characters to a limited extent, and produced 

 many seed. The several F4 plants grown varied widely as to awns and color of chaff and 

 kernel segregations being in a 3:1 ratio. The heads were wheat-like in appearance but in 

 some respects showed their hybrid origin, as did also the plants. Some were fully fertile, 

 others nearly sterile. Some F4 families have been carried further, being grown in the field 

 to test their winter hardiness. — C. E. Leighty. 



1732. Manson. Hereditary spastic paraplegia with ataxia and mental defect. British 

 Med. Jour. 2: 477. 1920. — One brother and 3 sisters each develop rather complex, but al- 

 most identical, syndromes of severe symptoms, beginning at about the 7th j'ear. Syphilis 

 and alcoholism are excluded. Both parents are alive and well, but the paternal grand- 

 father was an invalid concerning whom there is no further information. — C. II. Danfortk. 



