62 GENETICS [Bot. Absts., Vol. V, 



452. Scuindler, F. Bedeutung der Landrassen unserer Kulturpflanzen. [Significance 

 of local varieties of our cultivated plants.] Deutsch. Landw. Presse 1918: 155. 1918. 



453. Schmidt, Johs. La valeur de l'individu a titre de generateur, appreciee suivant la 

 methode du croisement dialleie. [Individual potency appraised by the method of diallel cross- 

 ing.] Compt. Rend. Trav. Lab. Carlsberg 14: 1-33. 1919.— See Bot. Absts. 5, Entry 302. 



454. Schroeder. Entstehung und Vererbung von Missbildungen an der Hand eines 

 Hypodaktylie-Stamrnbaumes. [Origin and inheritance of deformities in a hypodactylous pedi- 

 gree.] Mohatsschr. Geburtshilfe Gynakologie 48: 210-222. 3 pi. 7 fig. 1918. 



455. Shamel, A. D. Performance records of avocados based on citrus experiments. 

 California Citrograph 5: 68, 86-88. 1 fig. Jan., 1920. — Description of methods recommended 

 for obtaining records of yield and quality of fruit, hardiness, and other horticulturally import- 

 ant characteristics of avocado trees, as basis for selection of desirable types for propagation. 

 Organization suggested similar to the "bud selection department" of the California Fruit Grow- 

 ers' Exchange, which last season sold 230,000 citrus buds taken from superior trees. — H. B. 

 Frost. 



456. Sieqel, W. Das Recht des Gemiiseziichters. [The right of the vegetable breeder.] 

 8vo. Frick: Wien. 1919.— See Bot. Absts. 5, Entry 304. 



457. Siemens, H. W. Erbliche und nichterbliche Disposition. [Hereditary and non- 

 hereditary disposition.] Berlin. Klin. Wochenschr. 56: 313-316. 1919. 



458. Siemens, H. W. Uber die Grundbegriffe der modernen Vererbungslehre. [On the 

 fundamental concepts of modern genetics.] Munchener Med. Wochenschr. 65: 1402-1405. 

 1918. 



459. Siemens, H. W. Was ist Rassenhygiene? [What is race hygiene?] Deutschlands 

 Erneuerung 2 : 280-282. 1918. 



460. Smith, L. H. The life history and biology of the pink and green aphid (Macrosiphum 

 solanifolii Ashmead). Virginia Truck Sta. Bull. 27: 27-79. 12 fig. 1919.— Much variation 

 among individuals is found with respect to size of parts, color and reticulation within well- 

 known pink and green varieties. No inheritance of size variations has been noted. Strains 

 that differ from one another have been obtained. Sexual forms are not usually produced in 

 Virginia. Spring migrants are chiefly of green variety. Nineteen first-born and eight last- 

 born generations were reared from May to November, and 34 first-born generations in a twelve- 

 month period. Four molts occur. Average age at beginning of reproduction is eleven days, 

 average number of young produced by viviparous female is 45 during lifetime averaging 31 

 days. — A. Franklin Skull. 



461. Snell, K. Farbenanderung der Kartoffelblute und Saatenanerkennung. [Color 

 changes of the potato blossom and the recognition of varieties.] Der Kartoffelbau 1919: 1-3. 

 1919.— See Bot. Absts. 5, Entry 306. 



462. Sommer, K. tiber Kartoffelziichtung und vergleichende anbauversuche mit Neu- 

 ziichtungen auf der Domane Ellischau. [Potato breeding and comparative cultural tests of 

 new varieties on the Ellischau estate.] Nachr. Deutsch. Landw. Ges. Osterr. 1919: 190-193. 

 1919— See Bot. Absts. 5, Entry 307. 



463. Stahel, G. Eerste verslag over de werkzaamheden ten behoeve van de selectie van 

 KofBe en Cacao. [First report on the eifectiveness of selection in coffee and cacao.] Dept. 

 Landbouw in Suriname (Paramaribo) Bull. 36. 23 p. 1919.— See Bot. Absts. 5, Entry 308. 



