24 GENETICS [BoT. Absts., Vol. VII, 



167. Bower, F. O., J. Graham Kerr, and W. E. Agar. Lectures on sex and heredity 

 delivered in Glasgov/, 1917-1918. 16mo vi+llQ p., 49 fig. Macmillan Co.: London, 1919. 

 — Distinctly popular; profusely illustrated. Introduction: Terms defined (prefers "syngamy" 

 to fertilization); nature and function of sex discussed; its features contrasted with asexual 

 reproduction. (1) Origin of sex in plants: Origin and differentiation of sex illustrated by 

 Ulothrix, Ectocarpus spp., Fucus spp.; likens primitive isogamous plants to plant proletariat, 

 producing numerous offspring with little physiological capital, so that each individual when 

 produced must depend chiefly on its own efforts. Heterogamous forms, with well-nourished 

 eggs, are capitalists whose progeny start life with an inheritance. Parallel evolution in several 

 lines indicates that advantage is with latter; sex process in fern and angiosperm is described. 

 (2) Effect of fixed position on sexuality of plants : detailed discussion of fertilization mechanism 

 in fe ns, pollination and pollen-tube growth in angiosperms; advantages of "nursing habit" in 

 latter for their embryos. (3) Reproductive process in animals: some general principles;, 

 differentiation of sex illustrated by Copromonas, Stylorynchus, Plasmodium; in Copromonas, 

 discusses auto-intoxication which comes after generations of a sexual reproduction, and how 

 unfavorable conditions favor the sex act ; sketches embryology in higher animals, early differ- 

 entiation of gonads, continuity of germ-plasm, inheritance of acquired characters. (4) Modi- 

 fications of reproductive process as adaptations to life on land : adaptations by various frogs 

 and toads, representing "attempts to get rid of the free aquatic existence during the early 

 stages of the life-history;" gross embrj^ology of chick; monotremes, marsupials, higher mam- 

 mals; transplantation of ovaries; transmission of disease from mother to offspring. (5) Hered- 

 ity: Physical basis of heredity, using Cyclops as example; Darwin's pangenesis, Galton's and 

 Weism Ann's views; isolation of germ-plasm in Cyclops; inheritance of acquired characters; 

 Mendel's law, with Andalusian fowl as example; dominance illustrated by red X white 

 Antirrhinum [?]. (6) Heredity in man: Mendelian inheritance of brachydactyly; Galton 

 and Pearson laws applied to inheritance of stature, insanity, special ability, assertiveness, 

 popularity; dangers from multiplication of unfit, and differential birth-rates favoring non- 

 intellectuals. — Merle C. Coulter. 



168. Breakwell, E. Improvement of sweet sorghums. Agric. Gaz. New South Wales 

 31:549-551. 1920. — Summary of methods for securing improved strains. — L. R. Waldron. 



169. Brierly, W. G. Report of the division of horticulture. Minnesota Sta. Rept. 

 1919: 49-54. 1919. — Outlines the work on inheritance of fruit characters, on sterility in fruits, 

 on breeding for hardiness, and on breeding and selection of vegetables. — H. K. Hayes. 



170. Burns, W. Some aspects of plant genetics. Agric. Jour. India 15: 250-281. 1920. 



171. Carroll, Mitchel. An extra dyad and an extra tetrad in the spermatogenesis of 

 Camnula pellucida (Orthoptera) ; nximerical variations in the chromosome complex within the 

 individual. Jour. Morph. 34: 375-455. H pi. Sept. 20, 1920. — Ten specimens of Cam- 

 nula pellucida, an orthopteran of the family Acrididae, were used in this investigation. Of 

 these, five were seemingly unique in their cytological phenomena. Conjugation during 

 maturation of a homologous pair of supernumerary chromosomes and the occurrence of 

 "indisputable instances" of definite numerical variations within the individual in germinal 

 chromosome complexes in non-pathological tissue are the main things considered in the 

 paper. — The normal constituents of the complex are constant in number, and the aberrant 

 condition is due to the presence of a varying number of supernumeraries in different cells 

 within an individual. This variation is not constant for the gonad, but is constant for the 

 cyst, and probably constant for the follicle until after the first spermatocyte mitosis. — The 

 supernumeraries are all homologous in size, form, and behavior, and are apparently geneti- 

 cally related. Within one individual the extra element may be absent in some complexes, 

 unpaired in some, paired in others, and present in triplicate in still others. If unpaired, it 

 divides in only one division, usually the second. It is a matter of chance as to whether or 

 not it goes with the accessory chromosomes. If the supernumerary is paired it behaves as 

 any ordinary chromosome. If present in triplicate, two of the elements synapse and behave 



