268 



IRIS. 



are near hatching- : at that time the female is frequently fed by the male. 

 This is not common to all species, but very conspicuous in the rook, the 

 pigeon, and many others. Many species of birds possess a reservoir for 

 food, called a craw, or crop ; this seems to answer the same purpose as 

 the first stomach in ruminating" animals. Here it is the food is softened 

 and prepared for the stomach ; from this reservoir it is by some ejected 

 for the purpose of feeding- their young ; conspicuous in the pigeon. 



The rook has a small pouch under the tongue, in which it carries 

 food to its young. It is probable the use of the craw may be extended 

 further than is generally imagined; for, besides the common preparation 

 of the food to assist its digestion in the stomach, there are some species 

 that actually secrete a lacteal substance in the breeding season, which, 

 mixing with the half-digested food, is ejected to feed and nourish the 

 young. The mammae, from which this milky liquor is produced, are 

 situated on each side the upper part of the breast, immediately under 

 the craw. In the female turtle dove we have met with these glands 

 tumid, with milky secretion, and we believe it common to both sexes of 

 the dove genus. The cormorant or pelican genus possess no craw ; but, 

 to supply its place, they have a loose skin at the base of the under man- 

 dibles, capable of great distention, in which they carry fish to their 

 young. The bustard is said to possess a bag of an astonishing size, for 

 the purpose of retaining water ; but the most unaccountable and ex- 

 traordinary formation in the trachea of many of the males of the duck 

 genus, called a labyrinth, is beyond our reach to discover the use of, 

 as well as the singular flexure in the windpipe of the hooping swan 

 and crane. , 



It is much to be wished that naturalists would pay more attention to 

 these singular internal formations of birds ; it would no doubt throw 

 light on many obscurities in the division of species. The number of 

 tail-feathers should also be well ascertained, for this alone is a mark 

 of distinction, as in the cormorant and shag. 



INGRIAN FALCON.— A name for the Orange-Legged Hobby. 



INSESSORES (Vigors) — *Perchers, a numerous group of the 

 smaller birds.* 



IRIDES.— *The plural of Iris.* 



IRIS. — * The coloured circle of the eye, which in man is blue, 

 brown, grey, or hazel. In birds it varies very considerably.* 



