No. 3, January, 1922] GENETICS 165 



1073. Moore, Carl R. On the physiological properties of the gonads as controllers of 

 somatic and psychical characteristics. IV. Gonad transplantation in the guinea-pig. Jour. 

 Exp. Zool. 33: 355-3S9. 4 fig- 1921. — This is a continuation of the author's previous work. 

 Ovarian grafts in castrated male guinea-pigs lead to an hypertrophy of the teats, but no 

 hyacquisition of female instincts occurs. Testicular grafts in spayed females produces 

 hypertrophy of the clitoris, and male behavior. These results differ somewhat from those 

 obtained with rats. — //. D. Goodale. 



1074. Okkelberg, Peter. The early history of the germ cells in the brook lamprey, 

 Entosphenus wilder! (Gage), up to and including the period of sex diflferentiation. Jour. 

 Morphol. 35: 1-151. 12 pL, 4 fig. 1921. — This species shows juvenile hermaphroditism, with 

 males and females in approximately equal numbers in the adult condition. This indication 

 that sex is not irrevocably determined at time of fertilization and the lack of a complete ac- 

 count of germ-cell cycle for any vertebrate accounts for this work. Primordial germ cells are 

 first recognized (by their size, structure, and position) when the mesoderm begins to separate 

 from the entoderm before germ layers are definitely established (embryo about 191 hours old). 

 They lie laterally in the posterior region of the mesentoderm, later through shifting of sur- 

 rounding tissue and independent migration they come to a median position. The number is 

 small (36 were found in one larva). They are the sole source of definitive germ cells in both 

 sexes and never give rise to somatic tissues. From time of segregation up to 20 mm. stage of 

 the embryo (about 4 months) these cells do not divide. From 20 to 35 mm. an indefinite num- 

 ber of divisions occur. Larvae up to this time are indifferent as to sex. From 35 to 70 mm. 

 they become hermaphroditic as judged by the production in all gonads of large yolk-laden 

 cells, which are considered as egg cells. A series of gonads gives from to 100 per cent of 

 these large cells. Reproductive organs (gonads and accessory structures) are simple and 

 morphologically quite similar in adults of both sexes. This may be related to tendency of 

 species towards juvenile hermaphroditism. The author concludes: First sexual changes 

 appear in gonad, each of which contains 2 kinds of cells, those with tendency for rapid division 

 (katabolic) and those with tendency for growth (anabolic). Difference is considered to be 

 due to disturbance of metabolism of cells during mitoses or to environmental conditions. 

 Relative proportions of anabolic and katabolic cells determine whether larva becomes male 

 or female; therefore, sex is not irrevocably fixed at fertilization. The author grants that 

 sex is ordinarily an hereditary character associated with sex chromosomes but holds them to 

 be only one link in series of processes which determine sex, so that in a form like the lamprey 

 with very little difference between sexes other factors may overcome the effects of the sex 

 chromosomes; from this he infers that other hereditary characters may also be modifiable 

 and points out that should such prove true there would be less objection to the idea that sex 

 character may be modified. Secondary sex characters are probably not genetic but due to 

 hormone action. In addition, the paper contains an account of habits and life history, list of 

 important contributors to various theories of origin of germ cells in vertebrates with conclu- 

 sions of each, and an unusually full discussion of literature bearing on subjects of hermaphro- 

 ditism and sex-determination. — E. Eleanor Carothers. 



1075. PiNOT, P. E. Sur la germination des spores, sur la nutrition, et sur la sexuality 

 chez les Myxomycetes. [Germination of spores, nutrition, and sexuality in the Myxomycetes.] 

 Compt. Rend. Acad. Sci. Paris 173: 50-51. 1921. — The author replies to investigators who 

 have opposed his conclusions regarding the Myxomycetes, and restates his theory, which 

 holds that sexuality in the slime molds consists in the union of individual (+) and (-) m3'xa- 

 moebae to form plasmodia capable of fruiting. — A. F. Blakeslee. 



1076. Plahn, App. Die Bestimmung der Bruchfestigkeit der Getreidehalme. [The 

 determination of brittleness of cereal cxilms.] Deutsch. Landw. Presse 1920. — This article 

 deals with the tests for load of single stems and sections of stems recommended by Kraus and 

 Holdefleis, and brings investigational methods into a definite system. [From author's 

 abstract in Zeitschr. Pflanzenziicht. 8: 63. 1921.] — J. P. Kelly. 



