NATURAL HISTORY OF SELBORNE 107 



We found the case to be the same with the ring-tail 

 hawk, in respect to formation ; and, as far as I can 

 recollect, with the swift ; and probably it is so with many 

 more sorts of birds that are not granivorous. 



I am, &c. 



number of species, and probably exists among most of the true C^lculid^^ ; a large 

 black species, Eudynamys orientalis, has had its habits detailed by Mr. Blyth, in 

 "Contributions to Ornithology for 1850." It selects a species of Crow generally 

 for the foster-mother, and it is a remarkable instance of design that the eggs of 

 both birds are nearly similar in colour, that of the Cuckoo being rather smaller in 

 size. It is suspected that this species breaks the eggs of the Crow before deposit- 

 ing its own, and there seems little cause to doubt that it lays several eggs at the 

 usual periods, the same as other birds. The genus Dolychonyx, among the Icterine 

 birds, also breeds parasitically, while several species of birds depute the office of 

 incubation to artificial heat, of which the most remarkable is the hotbed-making 

 Megapodius of Australia. There is another form which this habit assumes, 

 commonality of hatching, as in Crotophaga^ where various individuals make use of 

 a common nest and hatch by turns. [W. J.] 



