506 ERNEST WARREN. 



the commencement of sitting and of hatching in the case of 

 all three hybrids. These dates are now given, and it will be 

 ■seen that the period of incubation varied from twenty-seven 

 to twenty-six days. 



As I am unaware of the normal incubation periods of 

 Cacatua galerita and Licmetis na sic a it is not possible 

 to make an interesting comparison as to whether hybridisa- 

 tion affects this period. It may be noticed that there is a 

 difference of only about twenty-four hours in the incubation 

 period of the three hybrids. It also must be noted that out 

 oi the two eggs (omitting the broken one) only one hatched, 

 ■:and in conjunction with the results on the former occasions 

 we must regard the large percentage of failure in incubation 

 as being due to the hybridisation. 



At the time of writing the account of the first hybrid, the 

 second hybrid was only three months old, and it did not 

 seem to be fully grown. Owing to these circumstances 

 details of the measureinents were not given. 



The second hybrid is now fifteen months old, and the bird 

 which died was three months old. It is interesting to ascer- 

 tain how far the brother hybrids resemble one another, and 

 for this purpose comparative tables are given for the non- 

 measurable and for the measured characters. 



From these two tables it will be at once clear thatalthongh 

 the hybrids bear a sti'ong resemblance to one another yet 

 they exhibit certain differences. 



By reference to Table I it will be seen that the second 

 hybrid on the whole does not come so near to the male- 

 parent in its non-measurable characters as do the first and 

 third hybrids. 



In hybrids 1 and 3, five of the characters are nearer to 

 those of Cacatua, four are more or less intermediate 

 between those of the two parents, and one is closer to that 

 of Licmetis. 



The various characters, however, are not all similar to each 

 other in the two hybrids. The colour of the naked skin 

 around the eye is very pale blue in hybrid 1, and ahnost, 



