( Ixxxv ) 



the saucer, jiist skimming the surface of the water, in the 

 manner of a frightened water-fowl such as the Grebe. 



" Their progression under water — comparatively slow, and 

 effected by means of a series of jerks — was clearly due to 

 flying rather than swimming, but they also made use of their 

 legs, the posterior pair being kicked out behind simultaneously 

 with the movement of the wings. 



" We found that individuals kept in confinement always 

 preferred to crawl about among the Spirogyra in preference 

 to any other water plant. Several were kept alive by Mr. 

 Britten for about a week. 



" One male was observed to make an unsuccessful attempt 

 to pair with a female on the surface of the water, by climbing 

 on to her back. A Corethra larva once seized a male by his 

 legs and held on for some time until induced to leave go by 

 means of a camel's-hair brush. 



" The small pond or clay-holein which all theexamples, except 

 one, were taken, contained the usual common aquatic insects in 

 abundance, and the vegetation was also of the usual pond type. 



" The occurrence of this species so late in the season is 

 interesting, as those taken by Lubbock * were obtained in 

 August, and for those recorded by Burton f and Enock % the 

 month is not given." 



Mendelian Heredity in relation to selection. — Prof. 

 PouLTON drew attention to two recent papers by Prof. H. S. 

 Jennings of Baltimore, U.S.A. : (1) " Observed Changes in 

 Hereditary Characters in Relation to Evolution " (Journ. Wash- 

 ington Acad. Sci., vol. vii. No. 10, May 19, 1917, p. 281), and 

 (2) " Modifying Factors and Multiple Allelomorphs in Relation 

 to the Results of Selection " (American Naturalist, vol. li, 

 May, 1917, p. 301). In (1) the author, referring to the dis- 

 coveries of the French botanist Jordan and to the work of 

 Johannsen on *■' pure lines," expressed the conclusions to 

 which many naturalists have been led, viz. " that most of 

 the heritable differences observed between closely related 

 organisms — between the members of a given species, for 



* Trans. Linn. Soc, 1863, vol. xxvi, p. 135. 



t Journ. Quekett Micros. Club, 1894-7, vol. vi, ser. II, p. 148. 



X Journ. Quekett Micros. Club, 1894^7, vol. vi, ser. II, p. 275. 



