464 SECTIONAL TRANSACTIONS,—M. 
been raised as the result of a successful cross between Up-to-date and Leinster 
Wonder. Apart from the promising economic value of the hybrids, they should 
prove useful material for the further investigation of the pollen problems. 
Correlation of Degenerate Pollen to Disease.—An example of pollen sterility 
accompanying a diseased condition in the plant is to be found in the Quercina 
type (formerly called Quercina mutant) in the Jimson weed described by A. F. 
Blakeslee in the Journal of Genetics, April 1921. The typical Quercinas have 
anthers containing cnly a few sterile (shrivelled) pollen grains. 
In potato, out of twenty-five varieties which showed markedly the Up-to- 
date type of degeneration, nineteen are recorded as being susceptible to wart 
disease. 
It is too early yet to deal with the morphological and physiological problems 
that lie behind the facts stated. The question whether these states of degeneracy 
are leading to a unisexual condition in many varieties, or whether they denote 
a hybrid origin, with accompanying disturbances of the sexual cells, remains 
to be demonstrated. 
REFERENCES TO PUBLICATION OF 
COMMUNICATIONS TO THE SECTIONS. 
AND OTHER REFERENCES SUPPLIED BY AUTHORS. 
Under each Section, the index-numbers correspond with those of the papers in the 
sectional programmes (pp. 408-464). 
References indicated by ‘cf.’ are to appropriate works quoted by the authors of 
papers, not to the papers themselves. 
General reference may be made to the issues of Nature (weekly) during and sub- 
sequent to the Meeting, in which résumés of the work of the sections are furnished. 
Section A. 
4. To be published in Astrophysical Journ. (Contributions of Mt, Wilson 
Observatory). 
7. Philosophical Mag., Oct. 1921. 
9. Expected to be published in Proc. Roy. Soc. Edinb. 
12. Cf. Sc. Proc. Roy. Dublin Soc., xvi, 18, Mar. 1921; Nature, vol. evii., June 23, 
1921; Engineering, Sept. 9, 1921. 
14, An earlier paper on this subject is to be published in Proc. Roy. Soc. Edinb. 
18. Cf. British Rainfall, 1921 (when published). 
29. Cf. Astrophysical Journ., 18, 287, Nov. 1903; Monthly Notices R.A.S., 58, 431, 
539; 76,15; 80,574; 81, 515. 
Section B. 
3. See Journ. Chemical Industry, Chemical Trade Journ., &c. 
7. Cf. Jaeger, ‘The Action of Light of short wave-lengths on some Organic Acids 
and their Salts,’ to be published in 7'’rans. Chem. Soc. 
12. Cf. Journ. Institute of Metals, 32, pp. 241-276, 1919; further matter to be 
published later in same. 
13. Engineering, Oct. 14, 1921. 
Section C. 
2. To be published in Scottish Geographical Mag. 
5. Expected to be published in Geol. Mag. 
9. Geol. Mag., Nov. 1921. 
