Aphil, 1920] GENETICS 1 I'.t 



types of the common wheats, because these types might be expected to appeal more 

 monly. The evidence suggests, rather, that the wild Palestine type might ha d "tiki- 



nally through :i natural cross and therefore may be regarded as a contemporary f'irrn. — 

 M. J. Dorsey. 



1013. MacCaughbt, Vaughan. Race mixture in Hawaii. Jour. Heredity 10: 90-95. 



Feb., 1919. — The second article dealing statistically with the diversity of race intermarri ■.. 

 in Hawaii. [For first article, see Dot. Absts., 3, Entry 269.] This paper presente data I 

 marriage combinations of Portuguese, Spanish, the native Hawaiian*, Americans, Brit 

 and Germans. In general, it was found that each nationality married largely within itself, 

 but that in each there was great diversity in matings, although the numbers of matings with 

 other nationalities were smaller. — M. J . Dorsey. 



1014. Magntjsson, H. Geschlechtslose Zwillinge. Eine gewohnliche Form von Her- 

 maphroditismus beim Rinde. [Sexless twins. A usual form of hermaphroditism in cattle.] 

 Arch. Anat. u. Physiol. 1918: 29-62. 3 pi., 8 fig. 1918.— The principal interest of this contri- 

 bution to the study of the intersexual condition of the female of two-sexed twins of cattle 

 is the description of 11 cases of the author. The cases are not described very exhaustively 

 but they contain valuable data on the anatomy of the free-martin, especially of some very 

 extreme cases of transformation involving the external genitalia to an unusual extent. The 

 material at the disposal of the author comprised 64 cases of "sexless heifers" found in the 

 market. In 37 of these cases a clear history could be obtained; all were twin to a bull. He 

 also had at his disposal one case of foetal two-sexed twins with a common chorion in which 

 large branches of the umbilical vessels of the two foetuses were in direct communication; 

 the ovaries of the mother showed two corpora lutea, one in each ovary. The author refers 

 to a more complete publication in Swedish on this material; but does not give the reference. — 

 The present paper includes some microscopical observations; the outstanding fact in this 

 connection is the general testis-like character of the gonad; — the albuginea is similar to that 

 of the testis; canals similar to seminiferous tubules frequently occur but lined only with a 

 cubical epithelium in which no spermatogonia or later stages of spermatogenesis occur; there 

 are usually inclusions similar in structure to the rete testis. No germinal epithelium ever 

 occurred and no ovarian follicles. The gonad is similar in all cases to a hypoplastic testis. 

 However, there is great variation in the individual cases. — All of the cases show a more or 

 less pronounced male condition of the internal organs of reproduction; testes, vasa deferent ia, 

 seminal vesicles and sometimes prostate; of the female organs the ovary and oviduct never 

 occur, the uterus is always much reduced, in many cases no larger than the uterus masculinus 

 of the bull; the vagina is extremely reduced. On the other hand the external organs of repro- 

 duction and the udder are almost always distinctly female in character. — The author holds 

 that the twins are monozygotic in spite of the cited fact that Tandler and Keller always 

 found two corpora lutea for such twins (in 17 cases) and that he himself found the same con- 

 dition in four cases of foetal twins. These facts are lightly disposed of. The author also 

 holds that both twins are of the male sex in spite of the fact that this interpretation raises 

 the percentage of same-sexed twins to 96 per cent instead of the expected 50 per cent. In 

 his theoretical interpretation he leans towards Hart's theory, that in the hypothetical divi- 

 sion of the assumed single male zygote to form twins the genital determinants are unequally 

 divided so that the "potent" male characters go to one twin and the "impotent" to the other. 

 The author, however, points out that this never happens in the case of the female zygote, and 

 moreover that the "potent" twin of the free-martin is a normal male possessing the so-called 

 impotent parts. — F. R. Lillie. 



1015. Mendiola, Nemesio Blanco. Variation and selection within clonal lines of Lemna 

 minor. Genetics 4: 151-182. 6 fig. Mar., 1919— This is a study of clonal variation and the 

 effect of selection on such variation in the duckweed, Lemna minor The work reported 

 extended over a period of one and one-half years and involved several thousand specimens. 

 The usual method of reproduction in Lemna is budding. Within a wild population races 

 were found to exist with fronds of diverse shape; no diversity was observed in the speed of 



