1^4 GENETICS [BoT. Absts., Vol. VII, 



obt's work on giant forms of Primula and on Sattndees's studies on linkage in stocks. Hor- 

 ticulturists generally should welcome suggestion of Miss SAtrNOERS, that there should be 

 more organized cooperation between all those sections of investigators and breeders interested 

 in laws of heredity and improvement in plants and animals. — Orland E. White. 



846. Anonymous. On the selection of Hevea brasiliensis. Kew Bull. 1920: 113-119. 

 1920. — Brief account drawn from Dutch sources. Improvement in rubber production may 

 be effected by (1) generative selection, isolation of high-yielding strains by seed selection, 

 and by (2) vegetative selection, multiplication of high yielders by grafting, budding, and 

 cuttings. Under (1) establishment of isolated seed nurseries made up of two high yielders 

 propagated by grafting is advocated. This method should be continued through successive 

 generations in order to isolate high-yielding strains. Artificial pollination is practicable, 

 and methods are described. Hevea appears normally to be self-sterile. Under (2) methods 

 of grafting and budding and of striking cuttings and securing good stock for cuttings are 

 described. Multiplication by cuttings is favored. In selection of trees high and constant 

 yield of latex is chief desideratum, but state of health and hereditary qualities are also con- 

 sidered. Introduction and trial of new types and species of Hevea may result in further 

 improvement. — R. E. Clausen. 



847. Anontmous. Hybrids of Gladiolus primulinus. Gard. Chron. 68: 105. Aug. 28, 

 1920. — Most hybrids of G. primulinus exhibit marked likeness to the same in form and elegance 

 but show considerable color variation. — J. Marion Shull. 



848. Anonymous. A mule in the vegetable kingdom. Tropic. Life 16: 139. 1920. — 

 According to the London correspondent of the North Queensland Register, Mr. F. J. Moore, 

 of Lion Creek in the Rockhampton District of Queensland, reports an apparent natural 

 hybrid between banana and paw-paw. A clump of bananas growing in close proximity to a 

 small paw-paw tree produced a bunch of fruit which looked like small plantains, but on 

 being opened they were found to contain seeds resembling paw-paw seeds. — H. N. Vinall. 



849. Anonymous. The genetics of strawberries. [Rev. of: Richardson, C. W. Some 

 notes on Fragaria. Jour. Genetics 10:39-46. 2 fig. July, 1920.] Gard. Chron. 50:211. 

 Oct. 30, 1920. 



850. Anonymous. The structure of the nucleus. [Rev. of: Agar, W. E. Cytology: with 

 special reference to the metazoan nucleus. XII + 224 P- Macmillan & Co.: London, 1920.] 

 Nature 105:482-483. 1920. 



851. Arber, a. The "Law of loss" in evolution. Proc. Linnean Soc. London 1919: 70-78. 

 1919. — Law of loss means the "general rule that a structure or organ once lost in the course of 

 phylogeny can never be regained; if the organism subsequently has occasion to replace it, it 

 cannot be reproduced, but must be constructed afresh in some different mode." Examples 

 cited are loss of roots in Ceratophyllum and Utricularia and substitution of special subterra- 

 nean shoots; failure of ciliated sperms to reappear in aquatic Angiosperms with submerged 

 fertilization; replacement of perianth in Naias with cupular outgrowth of receptacles; loss of 

 opposable thumb or great toe in tree kangaroo, with substitution of enlargement of claws; 

 and others from plants and animals. Operation of law of loss may be favorable "by closing 

 well-worn paths and thus indirectly encouraging the opening of fresh routes." — A. Franklin 

 Shull. 



852. Armbruster, Ludwig. Messbare phaenotypische und genotypische Instinktverand- 

 erungen. Bienen und Wespengehirne, neu verglichen und als Mass benutzt in Fragen der 

 Stammes- und Staatengeschichte sowie Vererbung und Genogenese. Nebst Anhang iiber 

 Nomada. [Measurable phenotypic and genotypic changes of instinct. Bee and wasp brains com- 

 pared anew and used as a measure in questions of race and state history as well as heredity 

 and genogenesis, with an appendix concerning Nomada.] Archiv Bienenkunde 1: 1-40. 5 pL, 



