No. 1, July, 1920] GENETICS 127 



Festschrift zur Feier des lOO-jfihrif^cri Bestehens der Kgl. Wiirtt. Landwirteoh. Hochsch. 

 Bohenheim. p. 2f>4-273. 4 fig- April, L918. -The size of the stigmatic papillae of Primula 

 can he experimentally modified, being dependent upon nourishment. By early defoliation 

 and subjecting the plants to darkness (he flowers arc greatly starved and tin- papillae corre- 

 spondingly reduced so that the lengths of the hairs on long-styled flowers, with mature well 

 developed Stigmas up to the time of pollination, are brought below the normal for the short- 

 styled forms. The latter are less influenced by this treatment. The modifical ion of the stig- 

 matic hairs or papillae is interpreted as osmomorphosis in the sense of Ktistcr. The lack of 

 nutrition, independently of the shortening of the papillae, may increase the distance from the 

 stigma to the ant hers in the long-styled form and decrease the distance in the short -styled form. 

 The degree of heterostyly will therefore sometimes be greater and sometimes less, so that in 

 ext reme cases hemostyly is produced. Pollen grain size is not modified in the same way as 

 the length of papillae. Even with great lack of nourishment part of the grains may have nor- 

 mal size. However, many abortive grains are shown, especially in Primula sinensis, as well 

 as grains above normal size. The Darwinian and Lamarckian correlation between the amount 

 of heterostyly and the development of the pollen and stigmatic papillae size can not be due 

 therefore to genotypical differences, but is best looked upon as a coincidence arising from the 

 morphological ecology. [See also Bot. Absts. 4, Entry 719.] — D. F. Jones. 



790. Tischler, G. Das Heterostylie-Problem. [The problem of heterostyly.] Biol. 

 Zentralbl. 38: 461-479. Nov., 1918. — Review of writer's previous publications (see Bot. Absts., 

 two preceding entries, 788, 789) and of the work of others on heterostyly in various species, 

 leading to the conclusion that the degree of this phenomenon is variable, due to the environ- 

 mental factors and can not be put on a genotypical basis. — D. E. Jones. 



791. Tischler, G. [Rev. of: Ernst, A. Bastardierung als Ursache der Apogamie im 

 Pflanzenreich. Eine Hypothese zur experimentellen Vererbungs- und Abstammungslehre. 

 (Hybridization as cause of apogamy in the plant kingdom. An hypothesis for experimental ge- 

 netics and evolution.)] 666 p., 2 pi., 172 fig. Gustav Fischer: Jena, 1918.] Zeitschr. indukt. 

 Abstamm. Vererb. 21: 130-134. July. 1918. 



792. Tischler, G. [German rev. of: Ziegler, H. E. Die Vererbungslehre in der Biol- 

 ogie und in der Soziologie. (Genetics in biology and sociology.) xvi+479 p., 8 partly colored 

 pi., 114 fig. Gustav Fischer: Jena, 1918.] Zeitschr. indukt. Abstamm. Vererb. 21: 192-199. 

 Sept., 1919. 



793. Tjebbes. [Rev. of: Heribert-Nilsson, N. Experimentelle Studien iiber Varia- 

 bilitat, Spaltung, Artbildung und Evolution in der Gattung Salix. (Experimental studies on 

 variability, segregation, speciation and evolution in the genus Salix.) Lunds Univ. Arsskr. 

 N. F. Afd. 2. 14 (No. 28): 1-145. 65 fig. 1918.] Genetica 1: 555-557. Nov., 1919. 



794. Tower, W. L. The mechanism of evolution in Leptinotarsa. Carnegie Inst. Wash- 

 ington Publ. 263. viii + 884 p., 19 pi., 161 fig. 1918. — In architecture of germinal material 

 author distinguishes two major kinds of agent, basal and definitive. Basal agents are prop- 

 erties of whole type and do not segregate. They are (a) basal factors, few in number, never 

 altered and never interchanged, probably mixture of ground-substance colloids, and (b) 

 chromatic receptors, substratum on which majority of determining agents are located (in 

 nucleus). Definitive agents are (a) few, always associated with basal factors in cytoplasm, 

 and (6) chromatic determiners, most numerous and commonly interchangeable in crossing. 

 Experiments have demonstrated in Leptinotarsa 9 basal factors (haploid number of chromo- 

 somes is also 9), and in some cases 2 chromatic receptors for each basal factor. About 50 

 chromatic determiners have been discovered, many of them capable of fragmentation. Fac- 

 tors make several things possible, determiners decide which occur. Location of agents un- 

 known, unlikely that observed phenomena are due to chromosome behavior. Reaction is 

 chemical, rather than morphological. Whole germ cells is germ plasm, not some part of it. 

 Eggs contain both factors and determiners, sperms only determiners. Female parent deter- 



