71 



the presence of several faunistic groups in our islands. These 

 groups must have had different areas of dispersal. The geo- 

 graphical conditions of the Central European plain during the 

 glacial period rendered it impossible to accept Mr. Taylor's 

 contention that that region must be regarded as an universal 

 centre of dispersal for all forms of life. 



The next paper was that of L. Don'caster, entitled : 



Sex-Limited Inheritance ix Ixsects. 



A. grossidariata and its form lacticolor, and the Dipteron 

 Drosophila anipelophila with its white- and red-eyed forms, as 

 examples of sex-limited inheritance. Tables showing the con- 

 stitution of the gametes in regard to two characters. Importance 

 of determining whether absolute coupling occurs between associ- 

 ated factors, and to what extent the sex is determined in the e^g 

 or in the spermatozoon. Desirability of discovering further cases 

 of sex-limited transmission. Probability that some insect which 

 can be bred with rapidity will provide the material required 

 (cf. Vol. II., p. 227). 



Discussion. 



N. C. Rothschild asked Mr. Doxcaster two questions: 



(i) If Mr. Doncaster had read a book called The Causation 

 of Sex, and if he agreed with the author's deductions, and 



(2) If an inherited character might not be inherited b}- a 

 child from its parent irrespective of the sex of that parent. 



Mr. Doncaster replied that he agreed with Dr. Rumley 

 Dawson, in believing that sex was determined in the c^^, but 

 that experiment did not support the view that one ovary pro- 

 duced male-determining eggs, and the other female-determining. 



As to the second question, it was important to distinguish 

 between the characters which showed sex-limited transmission, 

 and secondary sexual characters, i.e. those which appeared in 

 one sex only, though they were apparently transmitted to both. 



No further discussion ensued, and the meeting terminated. 



