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rous birds have commonly the longefl. villi ; in the goo/e and 

 /'■^•an they are fingularly beautiful, floating a confiderable 

 way into the cavity of the inteftine. The birds of prey, and 

 thofe which feed on fiih, have the villi in genera! fo fniall and 

 indiltinft, that on a flight infpeftion, the inner furface of 

 the inteftine appears quite fmooth. The O'wl, however, forms 

 a remarkable exceplion to this obfervation in having long and 

 pendulous villi. 



The vafcular proceffes upon the internal furface of the 

 fmall inteftines of the ojlrich do not polTefs the ufual villous 

 or hair-like form, but confill of very thin plates, or laraellx. 

 Thefe are Ihort, with tie edges fomewhat round, ar.d placed 

 not in fucceffion, but alternately one with refpect to another, 

 fo that each lamella ftands oppofite to the interfpace of the 

 two adjoining, by which means the furface of the inteftine 

 puts on very exattly the appearance of twilled cloth. The 

 ftrutlure producing this eftedl cannot be feen completely, as 

 may be iuppofed, without a magnifying glafs. 



We have not obferved in birds any thing analogous to 

 thofe projeclions of the internal coat of the Imall intellines, 

 which in other animals are called valvuU connivenles. The 

 Academicians, however, relate that they found in the bvjlard 

 the inner tunic of the ilium folded longitudinally, in the 

 manner of the laft; ftomach of ruminating animals, and that 

 towards the extremity of this inteftine there were fome tranf- 

 verfe wrinkles, which fupplicd the place of the valve of the 

 colon. 



Throughout the tradl of the inteftinal tube, we have dif- 

 covered fevcral clufters of mucous glands : where thefe are 

 fituated, the internal coat appears as if flightly ulcerated, or 

 not unlike a dyfenteric inteftine, infttad of that regular 

 dotted figure which the mucous glands commonly exhibit in 

 mammalia. 



The great intefl'tnes, as they are called, benr no fort of pro- 

 portion to the fmall, in point of length : in many inftances, 

 even where the latter are of confiderable extent, they do not 

 exceed a few inche?. They only admit of divlfton into two 

 parts ; the ccecal appendages, and the continuation of the 

 tube until it terminates at the anus. The Grft correfpond 

 with tlie inteftinum ccccum of mammalia ; and the other 

 takes the place of the colon and redlum ; but which from 

 its extreme ftiortnefs and direft courfe to the anus, would 

 appear to deferve only the name of reclum. 



The c<ecal appendages are fubjedl to as much variety as 

 perhaps any other part of the ftruclure of birds. Generally, 

 they are two in number; in which cafe, they arife rather ab- 

 ruptly from oppofite fides of the inteftinal tube, about the 

 place where the convolutions ceafe, and the inteftine becomes 

 ilraight. 



It may be received as a general rule, to which, however, 

 there are fome ftriking exceptions, that the magnitude of the 

 coeca is in proportion to the mufculaiity of the ftomach ; we 

 accordingly meet with this organ of the greateft fize, and 

 the ftrongeft charafters in the gaU'm.c and oxher gramhi'fvo- 

 roiis bird=i, from which it will be found moll convenient firft 

 to take the defcription. 



The cocca in thefe birds commonlv afcend for fome way 

 quite clofe to each fide of the inteftine, from which they 

 arife ; during which they are lefs than the other parts of the 

 inteftinal canal ; they then make a flight curve outwards, 

 and become fomewhat enlarged, and towards the fuperior 

 extremity lUey again diminifli before their termination in the 

 cul de fac. Thefe parts reach up in the abdomen to near the 

 liver, and often make a flight curve round the fpleen ; they 

 are connected to each other, and to the inteftine between 

 them, and alfo retained in their relative fituation in the ab- 

 domen, by refledions of peritoneum, of which fome are ana- 

 logous to the mefo-colon and mefo-reftum, and others con- 



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tribute to the formation of the air-cells. See Plate III. in 



the Anatomy 'if Birds. Fig. 3. reprefents thofe parts in the 

 pintado, or guinea-hen ; a the laft portion of the fmad inteftine 

 placed Letween the two coeca, bbiht cocca, c the rectum, ddd 

 the peritoneum connefting thofe parts, fa procefs of perito- 

 neum paffing acrofs from the top of one coecum to another. 

 If the ccecabeflit open, it is found that_ihev communicate 

 with the rcftum by an aperture which is fn.aller than their 

 own cavity at the place ; and confequently, any fubflance 

 will pafs with difficulty into them from the other intcftir.es, 

 and likewife be obftruAed in its return. 



Juft within the entrance of each ccecum., there is a cluf- 

 ter of m.ucous glands, which appear like two fpots of ulcera- 

 tion. Thefe are particularly ufeful in this fituation to fmooth 

 the paftage of fubftances in and out of the cccca. 



The contracted parts of the cccca are in fome degree vil- 

 lous on the inner furface, and refemble in ftrutture the reft 

 of the inteftinal canal ; but the dilated parts are deprived of 

 villi, poflcfs very little vafcularity, appear to have few, ifanv, 

 mufcidar fibres, are without mucous glands, and arc little 

 better than fimple membranous tubes. Thefe parts contain 

 the exuvix of the food. 



All the ufes which the cceca ferve to animals are certainly 

 not yet known ; and the functions of thefe organs in birds 

 are amongft the leaft underftood. The magnitude of their 

 cceca is not always in proportion to the apparent necclTity 

 for fuch refervoirs ; often, where they might be expected 

 large, they are fmall, or abfent altogether, and fometimes, 

 where the nature of the food would not feem to need thefe 

 repofitories, they are of confiderable fize. With the view of 

 determining their ufes, they were removed from the living 

 hen, and the confequence is faid to have been, that the ani- 

 mal would not admit any food from the crop into the giz- 

 zard, from which it might be inferred, that their organs 

 ferve other and more important purpofes in the animal 

 economy, than mere refervoirs of excrement ; that, how- 

 ever, they are employed as a foit of temporary fcwers, to 

 receive the undigeftcd parts of the food, is obvioufly true ; 

 and that in doing fo, they anfwer an ufeful purpofe, appears 

 to be proved, in defpite of many exceptions, by the more 

 numerous inftances of their bearing a decided relation to the 

 digeftive organs, and the quality of the food. 



The fame ftrufture which has been defcribed in ihe guinea 

 hen, or pintado, is to be found with little variation in ail 

 the gaUin<s ex;cept the pigeon, and in the herbivorous anferes, 

 fuch as the/ii'an, ihe goofe, lye. 



Daudin dcfcribes the cccca of the heath-cock {^fetrao uro- 

 gallus), and of the •mhite grous {lelrao lagopus), as grooved or 

 fluted longitudinally. 



The cceca of the ojlrich are different from thofe of other 

 birds ; they are large where they commence, and dimimlh 

 gradually towards their termination ; they fuffer many con- 

 volutions in confequence of a longitudinal band upon the 

 pofteriorfide, which is only two thirds of their length ; they 

 are facculated, or divided into loculi, througliout their vhole 

 extent, by means of a valvular projection of the internal 

 coat, which winds in a fpiral manner, fimilar to the valve of 

 the coecum in' the have and rabbit in mammalia, or the raj 

 zndjharh kind amongft fifli. 



The fpiral lamina is about five lines in breadth, but be- 

 comes fomewhat lefs towards the extremities of tiie coica. 

 This lamellated ftrutlure is continued for fome way into the 

 other great intiftine, and even into the fmall inteftines ; not, 

 however, as one fpiral valve, but in feveral tianfverle pro- 

 jeftions, which have a femilui.ar figure, and are placed alter- 

 nately, fo that one lamella is received between two others, 

 in the manner of the denticuli of the bivalve /hells. P/ate 

 III. Jig. 4. is a portion of the firft part of the great inteftine 

 3 E 2 or 



