102 GENETICS [Bot. Absts., Vol. VI, 



is found to be depressed. The modifications of the variability curves noted are probably 

 related rather directly to nutritional conditions. Heredity and suboptimal nutrition are 

 believed to be responsible for the half-curve variability. — Charles A. Shall. 



721. Shull, J. Makion. Concerning Iris colouration. Gard. Chron., 67: 291. June 12, 

 1920. — Author presents observations on ncglccta forms of Iris, which are colored forms lack- 

 ing yellow plastids, and points out that it is to be expected that such will show a clear purple 

 or violet rather than a brownish coloration, since latter is composite effect of anthocyanin 

 and yellow plastids. Further observes that yellow occurs in both "standards'' and "falls" 

 while anthocyanin may not be so distributed. Non-hereditary freak bearing on brownish 

 and purple coloration is also described. — James P. Kelly. 



722. Sirks, M. J. Erfelijkheids- en selectieonderzoekingen bij Vicia-soorten. I. De 

 Navelkleur van Vicia faba. [Inheritance and selection experiments in Vicia species. I. The 

 eye-color of Vicia faba.] Genetica 2: 193-199. May, 1920. 



723. Sirks, M. J. [Dutch rev. of: Castle, W. E. Studies of heredity in rabbits, rats 

 and mice. Carnegie Inst. Washington Publ. 288. 56 p., 3 pi. 1919.] Genetica 2: 248-251. 

 May, 1920. 



724. Sirks, M. J. [Dutch rev. of: Dahlgren, K. V. Ossian. Erblichkeitsversuche mil 

 einer dekandrischen Capsella bursa-pastoris (L.). (Gentical investigations with a decandrous 

 Capsella bursa-pastoris (L.).) Svensk Bot. Tidsskr. 13: 48-60. 2 fig. 1919. (See Bot. 

 Absts. 3, Entry 616.)] Genetica 2 : 254. May, 1920. 



725. Sirks, M. J. [Dutch rev. of: Fruwirth, C. Handbuch der landwirtschaftlichen 

 Prlanzenzuchtung. 3. Die Ziichtung von Kartoffel. Erdbirne, Lein, Hanf, Tabak, Hopfen, 

 Bucliweizen, Hulsenfruchtern und kleeartigen Futterpfianzen. (Handbook of agricultural 

 plant breeding. 3. The breeding of potatoes, Jerusalem artichokes, flax, hemp, tobacco, hops, 

 buckwheat, legumes and clover-like forage plants.) 3rd ed., 240 p., 45 fig. P. Parey: Berlin, 

 1919.] Genetica 2: 257. May, 192'). 



726. Sirks, M. J. [Dutch rev. of: Fruwirth, C, Th. Roemer, E. von Tschermak. 

 Handbuch der landwirtschaftlichen Prlanzenzuchtung. 4. Die Ziichtung der vier Haupt- 

 getreidearten und der Zuckerriibe. (Handbook of agricultural plant breeding. 4. Breeding 

 of the four chief cereals and sugar beets.] 3rd ed., 8vo., xv + 504 P-,4® fid- Paul Parey: Ber- 

 lin, 1918.] Genetica 2: 256. May, 1920. 



727. Sirks, M. J. [Dutch rev. of: Schaxel, J. Grundziige der Theorienbildung in der 

 Biologic (Principles of theory formation in biology.) 221 p. G. Fischer: Jena, 1919.] 

 Genetica 2: 267-268. May, 1920. 



728. Sirks, M. J. [Dutch rev. of: Schaxel, Julius, tiber die Darstellung allgemeiner 

 Biologic (On the presentation of general biology.) Abhandl. Theoret. Biol. 62 p. 1919.] 

 Genetica 2: 268-269. May, 1920. 



729. Sirks, M.J. [Dutch rev. of : Tischler, G. Ueber die Sogenannten "Erbsubstanzen" 

 und ihre Lokalisation in der Pflanzenzelle. (On the so-called hereditary substances and their 

 localization in the plant cell.] Biol. Zentralbl. 40: 15-28. 1920.] Genetica 2: 271-273. May, 

 1920. 



730. Sirks, M. J. [Dutch rev. of: (1) Tower, W. L. The mechanism of evolution in 

 Leptinotarsa. Carnegie Inst. Washington Publ. 263. viii + 284 P-, 19 pi., 161 fig. 1918. 

 (See Bot. Absts. 4, Entry 794.) (2) Breitenbecher, J. K. The relation of water to the be- 

 havior of the potato beetle in a desert. Ibid. 263. 340 p., 19 pi. 1918.1 Genetica 2: 274-277. 

 May, 1920. 



