THS DIGESTIVE APPARATUS l\ /;//;/>. 



In <;u!h'ii,i::> (I i.'. -2-21. ::. I. " . this dilatation dues not cxi.-t ; l.ut tlio 



:ts in it.- eoiir-e. and immediately In-fore entering tl.o cln -t a-i ovoid 

 pooch named the ero/i IT iiujhirii*.) In tin- u->opl.a'.:n.- <i tln-.-c birds, th. n. we find 

 t\\o di.-tiin-t M-. -tic.il:-, joined end to rial one superior cr ccrvic.d. tin- otln i infer. or or 

 thoracic <-n tin- limit of which is tin- //<. The latter i!<xs not ditler in it- .-trm-tur.- 

 from the Oesophagus, and is a temp. r.,n reservoir lir the food s\\a'lowed by the nninial 

 dnrinu' it- meal, and where it i> soft< ned by leiiig impic<:nati d with u ceituin quantity 

 of tluid: after which it is parsed into the sin-centric ventricle by the contractions of tin; 

 external nienil>rane of the crop, aided by a wide subcutaneous cervical muscle, which 



Toir. 



In Pigeons, the crop is also present ; lint it is divided into !\vo lateral (nnic-hes, :md 

 exhibits glandular eminences t-.\\ard< the roiiiinoii inferior o|n-ning of lli. -. MI.-- into tin: 

 :iuru-. -'Otherwise, .-insular change., an- obs. -rved in tliti apparent t-trnctnr. of it- 

 walls in the male as well as in the female, during incubation, or during the tir.-t weeks 

 uftT hatching." (Hunter was the tir-' this: '< >b.-ervations on Certain 1'artj 



of tin; Animal Kconomy,' London, 17'.2). "At thi.-i iK-riinl. the membrnnes of ihe cn.|, 

 Uf .me thickened: the vessels, num- numerous and more ajijiarciit, tire redder, a'.id the 

 irlunds more d< \eloj <1. The internal surf.ice is divided by folds or ridges, which cross 

 each -i her, and form triangular meshes ; while on apparently milky fluid is poured out 

 from the r-ecr. t .iv IHUI s into the cavity of the crop. Pigeons exclusively nourish tin ir 

 }oiing with this fluid during the lirr-t three <lnys i>{ their existence." ' 



SIX>MACH The stomach presents numerous variations in birds. Its simplest form is 



:n tin- heron, pelican, p. treks, etc., where it is a single sac provided with a thick 



f plands around the entrance of the oesophagus, which secrete the gastric juice. 



15nt in the majority of the other species, and particularly in our domesticated birds, the 



di.-]>sition of the stomach is modi lied and complicated ; the glandular zone destined for 



the gastric secretion forms a special compartment the succentric rentride, and this is 



followed by a stcoud reservoir the gizzard, which is remarkable for the strong muscular 



utioii (if its walls. The first is also named the glandular stomach, and the second 



the mutcular stomach. 



Glandular stomach, or succentric ventricle (provenlriculus) (Fig. 221, 6). This is an 

 ovoid sac placed in the median plane of the body, between the two lobes of the liver, and 

 beneath the aorta. Its anterior extremity receives the insirtion of the oesophagus; the 

 <r i- continued by the gizzard The volume of this stomach is inconsiderable, nnd 

 its cavity is very narrow; the aliment does not accumulate in it, but merely passes 

 through, carrying with it the acid juice which afterwards dissolves its prot. in elements. Its 

 walls have three tunics : an external or peritoneal : a middle, formed of white muscular 

 fibres, continuous with those of the oesophagus; and an internal, of a muroiu nature, p. r- 

 forated by orifices for the passage of the gastric juice. These are small cylinders placed 

 }T|-ndicuIarly to the surface of the stomach, closely laid against one another, like the 

 microscopic glands of Lieberkilhn, and contained in the cellular layer uniting the inner 



middle tunic. The d.indnlar .-trueture of this ri-c.-ptadc Mitlici. ntly d 

 that it should !> as.-imilated t" the ri^ht sac of the .-toiuai-h in Solipeds, and therefore 

 jitrded as the true stomach. 



. nnnutcultir stomach ( rentrii ulut bnlbogu*) (Fi-. '2'2l. 7). Much more volu- 

 minous than the preceding, this stomach is oval in form, depressed on each side, and 

 situated behind tin- liver, being partly covered by the lateral lobes of that gland. At \>-, 

 and to the riu'lit. and at a short distance from each other, are seen the insertion of tin- 

 le nnd the origin of the duodenum. The cavity of tin- -iy/ard :d\\a\s 

 d mix.-d uith a large quantity of silicions pebbles, whose use will be fndkated 



This viscera is composed of the three tunics which form the walls of all the 



abdominal n-M-rvoirs. The intern il, or mucous, is dilttaguWted by the thickness and 



extraordinaiy induration of its epidermic layer, wliich presents m arly all th- 



of homy tinoe, and is so easily detached fiom the mnc,.u.- choiimn that it is oft. n 



regard ial nu-inbiain-. On the adherent face of tl.U corium tire applied tun 



powerful red im, iperiorand inferior, occupying tl.e honh rs >f tin- iT-aii. ai.d 



libn-, di.-p'cd in HI-MIP-S, psisw from side t" side, and d into a t-trong, 



n iht- lateral surfaces of Iho organ. Outside this contractile 



a thill p> riloneal envelope. 



gizzard is the triturating apparatus of birds. When the aliment icachee its cavity 



'luitte*! t" any d s ej-re^ation, but here it meets with all the condition's 



I . v .ns d'Anatomic Comparce de <J dm, r.' '.'lid 1 



