302 NATURAL HISTORY 



or craw, and immediately behind that, the bowels 

 against the backbone. 



It must be allowed, as this anatomist observes, that 

 the crop placed just upon the bowels must, especially 

 when full, be in a very uneasy situation during the 

 business of incubation ; yet the test will be, to examine 

 whether birds that are actually known to sit for certain 

 are not formed in a similar manner. This inquiry I 

 proposed to myself to make with a fern-owl, or goat- 

 sucker, as soon as opportunity offered: because if their 

 formation proves the same, the reason for incapacity in 

 the cuckoo will be allowed to have been taken up some- 

 what 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 sus- 

 picions ill grounded ; for, upon the dissection, the crop, 

 or craw, also lay behind the sternum, immediately on 

 the viscera, between them and the skin of the belly. 

 It was bulky, and stuffed hard with large Phalcence 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 practise incubation, is formed in a similar 

 manner with cuckoos, Monsieur Herissant's conjecture, 

 that cuckoos are incapable of incubation from the dis- 

 position 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*. 



a The cuckoo has no true crop, and the position of its proventriculus 

 does not differ from that of other scansorial birds; the oesophagus de- 

 scends along the posterior or dorsal part of the thorax, inclining to the 

 left side, and, when opposite to the lower margin of the left lung, it begins 

 to expand into the glandular cavity or proventriculus. The gizzard, 

 which is neither large nor strong, is in immediate contact with the abdo- 

 minal parietes, not separated from them by an intervening stratum of 

 intestines; but this position cannot be supposed to interfere with the 

 power of incubation, since it occurs also in other birds that do incubate, 

 as the owl and Caryocatactes. R. O. 



