14. Birds have their internal parts different from each other and from other animals; for some have before the stomach a crop, as the domestic fowl, pigeon, dove, and partridge. The crop is a large and hollow skin, into which the food is received before it is digested. Hence from the œsophagus it is narrower, then wider, and where it descends into the stomach it is smaller. 15. In most birds the stomach is fleshy and thick, and on the outside there is a strong skin, which is separated from the fleshy part. Some birds have no crop, but instead of it a wide œsophagus, either wholly so, or in the part extending to the stomach, as in the colœus,[83] raven, and crow. The quail has the lower part of the œsophagus broad, the ægocephalus has it small but wider, and so has the owl. But the duck, goose, gull, diver, and bustard, have a wide and broad œsophagus, and so have many other birds. [83] Three kinds of birds are called by this name. Corvus graculus, C. monedula, and Pelicanus graculus. 16. And some have a part of the stomach itself like a crop, as the cenchreis;[84] and there are some which have neither œsophagus nor a wide crop, but a large stomach; these are small birds like the swallow, and the sparrow. A few have neither a crop, nor a wide œsophagus, but a very long one; these are birds with a long neck, as the porphyrion.[85] Almost all these emit a moister excrement than other birds. [84] Falco tinnunculus. [85] Fulica porphyrion. 17. The quail has these peculiarities, for it has a crop, and before the stomach a wide and broad œsophagus. And the crop is at a great distance from the part of the œsophagus before the belly, considering the size of the bird. Birds have generally a small intestine, which is single when unfolded, and birds have appendages, a few, as I have said, and not placed above, as in fish, but below, near the end of the intestine. Some birds have not these appendages, though they generally have them, as the domestic fowl, partridge, duck, night-raven,[86] localus,[87] ascalaphus,[88] goose, bustard, owl. Some of the small birds have them, but they are very minute, as the sparrow. [86] Ardea nycticorax. [87] Some kind of heron. [88] Some kind of owl. BOOK THE THIRD. CHAPTER I.