NATURAL HISTORY OF SELBORNE. 203 
the reason for incapacity in the cuzkoo will be allowed to have been 
taken up somewhat hastily. 
Not long after a fern-owl was procured, which, from its habit 
and shape, we suspected might resemble the cuckoo in its internal 
construction. Nor were our suspicions ill-grounded ; for, upon the 
dissection, the crop, or craw, also lay behind the sternum, immc- 
diately on the viscera, between them and the skin of the belly. It 
was bulky, and stuffed hard with large p/alene, moths of several 
sorts, and their eggs, which no doubt had been forced out of those 
insects by the action of swallowing. 
Now as it appears that this bird, which is so well known to prac- 
tise incubation, is formed in a similar manner with cuckoos, 
Monsieur Herissant’s conjecture, that cuckoos are incapable of 
incubation from the disposition of their intestines, seems to fall to 
the ground ; and we are still at a loss for the cause of that strange 
and singular peculiarity in the instance of the cuculus canorus.* 
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. 
IT am, &c. 
* There is nothing in the anatomical structure of the cuckoo to prevent its performing 
all the duties of incubation ; parasitism is extended over a considerable number of species, 
and probably exists among most of the Cuculidw; a large black species, Eudynxamys 
ortentalis, 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 depositing 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 Dolyconyx, among 
the /cferzne 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, common- 
ality of hatching, as in Crotophaga, where various individuals make use of a common nest 
and hatch by turns. The whole subject is very curious, but there is a difficulty in pro- 
curing exact details of the habits of foreign species. 
