B I R 



the tongue. They would feem to be of the greateft fize in 

 proponion to the Mrd, where the food is hard and dry grain ; 

 they arc larger in the cotnnwn fozvl than in the gbofe. 



The I'arifKin academicians obferved thtfe glands in aimed 

 every bird they diflTefted. In the nJli'tL-h they defcribe them 

 as btincj litiiatid tou;irds the pharynx ; and in the lujlard, 

 thcv found leveral glandular bodies. 

 Otjophagus. 



The tube, which conveys the food into the ftomach of 

 birds, is not fif.iated exactly on the fore part of the 

 neck, but a little on the right lide. It is partially co- 

 vered by liie trachea, and it is connefted to all the neigh- 

 bouring parts by loofe cellular fuhllaiicc ; in confequencc of 

 which, and its inchnation to one ^\A<:, when the neck is much 

 bent, it does not take the fame degree of flexure, but fall? a 

 little off to the right iide. This effeA is bell obferved in 

 fonie of the birds which have long and flexible necks, as the 

 gralli and tunler lirils. 



The form of the rcfophagus varies according to the habits 

 of the bird, and the nature of its food. In the rapacious 

 birds, and tliofc which fubfdl: on fid), it is of great capacity 

 throughout its whole length, generally exceeding in width 

 the llomach iti'elf. Tt.e mag^it^lde of the oefophagus not 

 onlv enables thofe birds to fwallow their prey whole, but 

 anf-.vers the purpofe of a repofitorv for their food, and thus 

 counterbalances the difad^antagcs ariling from their preca- 

 rious means of fubfillence. 



Herons, the curmornnl, ihe fpoon-bill. Sic. will devour as 

 much fiih at once as will be futficieiit to fnpport them for a 

 confiderable time ; and an cW is often obliged to exift for 

 davs or weeks upon a rat or nioufe, which being fwal- 

 lowed, is conveyed by degrees into the ftomach, until the 

 whole K digeflrd. 



All the pifct-uorous birds have the ccfophagus mod capa- 

 cious at its commencement, or next the fauces, for the more 

 convenient fwallorting of their prey, which is always gulped 

 down. 



The ptiir/jn fnrnifhes a moft remarkable inftance of a dila- 

 tation of the fauces, in the pouch which is placed beneath 

 the lower jaw. This bag, if full, is very coifpicuous ex- 

 ternally ; but when it is empty, tho bird has the power of con- 

 tracting it very confiderably ; when completely diftended, it 

 is faid to be capable of containing ten quarts of water. The 

 internal part ot the pouch appears to potTefs the fame ftruc- 

 ture ?6 the reft of the cefopliagus ; the flein covering it ex- 

 ternallv, is clothed with a (horc down, fmooth and foft, 

 like fdk. 



The ptlkan derives a double advantage from this enlarge- 

 ment of the fauces ; it enables it to provide a fi.'pply of food 

 and water for future neceflity. and to tranfport nourifhment 

 to its young, until they can acquire it for tliemfclves : in dif- 

 gorging the food for her family, the parent pretfes the bot- 

 tom of the fack agsinft her breaft, and thus difcharges its 

 contents ; from which probably arofe the abfurd fable of her 

 opening her breaft, and feeding her young witti her blood. 



A very remarkable provilion of this kind lias been dcfcribed 

 ;in the luf.aril, by Dr. James Douglas. In this animal there 

 is a D.en-ibranous bag, extending for fome way down the 

 -fore-part, of the neck, cap.ible of containing feven quarts of 

 water ; it communicates with the month by an aperture be- 

 neath the tongAie. See PliUe I. fg. i. in the Anatomy of 

 ■Birds, in which -this part is reprefented, as it has been fi- 

 gmed in Edwards's Natural Hiftory of Birds, vol. ii. p. 73. 

 a the pouch, upon which a ligature is faftened near its con- 

 ■ciexion with the mo.ith, i the trachea, and c the oefophagus. 



Tlie pouch of the buftard is confined to the male bird, ac- 

 CPfding io moll authors ; forac have, however, afcribed it 



B I R 



to the female, and others have doubted its exiftence altoge- 

 ther. The Panfian academicians difieAed fix buftards, and 

 do not defcribe the throat fac, although all their fubjecls 

 were mall s. 



The buftard is faid to ufe the pouch, as a temporary re- 

 fervoir of water, from which it fupplies the female during 

 the period of incubation, and likewife the young brood, un- 

 til they can move from the neft. ll has been alio occafion- 

 ally employed as the means of defence. Harrington relates in 

 his Mifcellanies, p. 555. that at Morocco, where it is ufual 

 to fly the hawk at the buftard, the latter has been known 

 to ejeft the water contained in the fack againft his alfailant, 

 who is not uncommonly by this means bafHcd in the purfuit. 



The crrip, or craw, is a term applied to another Xpecies 

 of dilatation of the ccfophagus of birds. 



When this enlargement is fiiigle, it is fituated upon the 

 right fide of the oefophagus, and placed fo low on the neck, 

 that a portion of the bag is accommodated in the fpace left 

 at the upper part of the thorax, within the fork-lhaped 

 bone. Its form is in general globular, but rendered fome- 

 what irregular, from its connexion w;th the ccfophagus, 

 which enters at the fuperior part, and appears again on 

 the middle, by which means the greater part of the crop is 

 formed into a cul de fac. 



It is obvious, that the effeft of this ftrufture is not only 

 to receive a greater quantity of food than can be di^efted, 

 but alfo to detain it in the craw until it has fuffered fome 

 change. 



The birds in which the craw is found of the figure jufi. 

 dcfcribed, feed ufually upon grain or other hard fubftances, 

 which req'jire to be foftened by maceration in the mucous 

 fccretion oi the oefophaguf. Of thefe we may mention as 

 inftances, the pheafants, the common fcivl, the pmtadoy the 

 turkey, the Indian cock, ihc pca-foojl, iic. 



Fig. 2. of Piate I. in the Anatomy of Birds, exhibits the 

 crop of the ph:cifant, a the oefophagus above the craw, b 

 the fame going on to the ftomach, c the dilated part forming 

 the crop. 



The Parifian anatomifts found the oefophagus verj- much 

 enlarged in the ojlrich, but fo clofe to the gizzard that 

 thefe two parts appeared to be confounded with each other ; 

 fo that it was difficult to mark the fuperior orifice of the 

 ventricle ; the fituation of the bag alfo was very unufual, 

 being lower than the gizzard, into which the entrance was 

 by the bottom, and thus what is commonly called the fupe- 

 rior orifice, was really the inferior. 



It is fomcwhat remarkable, that the hujlard, which is a 

 graminivorous bird, and in moft refpefts refembles thole 

 which have crops, fhoiild be quite without this provifion, 

 its ccfophagus confifting of an equal and regular tube. 



The parrot has a dilatation of the lower part of the cc'o- 

 phagus, which is commonly reckoned to be a crop, though 

 perhaps improperly, as the enlargement is neither fo fud- 

 denly produced, nor in fuch a degree, as to obftruft the 

 pafTage of the food into the ftomach ; the craw of the par- 

 rot IS only calculated, therefor*, to afford a temporary ac- 

 commodation to its food. 



Some carnivorous birds are furnifhed with a cnw, which 

 only ferves the purpofe of a refervoir, as their food does 

 not (land in ne^d of maceration to foften it, which is fo 

 neceftiiry with hard and dry grain. 



The moft fingular kind of crop is that found in r.he pigeon 

 jIfenuF. The ccfophagus in thefe birds is of great capacity, 

 from its very commencement, and at its lower part it fweils 

 out into two large facks, between which and the llomach it 

 fuffers a confiderable contradion. See Plate I. of the Ana- 

 tomy of Birds, fig- 3. a the upper portion of the oefophagus, 



h, h. 



