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or colon of the ejlrkh, repre fented of the natural fize and cut 

 aorofs to rtitw tfie fcmicirciilar lamina on the infidc. 



The efFeft of this llrudiire is obvioiifly the retention of 

 the cxcrcmentitious part of the food for a iongc;- time in 

 the cceca ; which is accomplidied in other inllanccs by 

 the fmaUnefs of the aperture through which tlufc parts 

 communicate with the other intcftincs. This organ is not 

 limilar in the other Jliuthwus birds. Accordii'g to the 

 Parifian difleiftors, the cnffbivary is not provided with any 

 coecum. In the r^^a'arv, or (with mere propi if tyj o/?r/VZ', 

 of New Holland, we have found two cxcal appendages, 

 which opened into the re£lum by orifices not mueh larger 

 than pin-holes. The internal furfaces had none of the la- 

 minse, or valvular projeclions, but were furnillied with fine 

 vafeular fioccuH, fimilar to thofe of the fmall iuteflines of 

 the oflrich ; with this difference, that in the New Holland 

 bird, they are placed longitudinally, and are more loofe and 

 pendulous, looking fomewhat like lacerated portions or 

 ihreds of the inner coat of the intelline. 



In by far the greater number of birds the coccal appen- 

 dages are too fmall to ferve any purpofc, and appear only 

 as ufclefs imitations of the flrufture dcfcribcd in \\\c i^ramhii- 

 •vorous kinds. Many, that live on a mixt food, anil whofe 

 flomachs are of an intermediate ftrength, amongll the larger 

 pajpres, tlie pica of Ivinuasus, the grall<c, and the anferes, 

 liaTC two cocca meafuring in length ufually about twice or 

 thrice the width of the inteftine from which they take their 

 origin. See Plate \\]. Jig. 5. which exhibits thefe parts in 

 the gull. Coeca of this fizc have hjrdly any cavity, ar.d 

 feldom receive any of the contents of the other inteftines ; in 

 the fmall pafferes, which feed upon feeds, as the fparroiv 

 anijinch tribes, the cceca bear a Hill lefs proportion to the 

 fize of the reft of the inteftinal canal ; kejig. 6. of F/a/e 

 HI. in which the cceca are reprefented as they are commonly 

 found in thofe birds. 



In the pigeon the coccal proceffes are fo fmall, that they 

 efcaped the notice of fo accurate an anatomift as Severinus, 

 vho dtfcribed the pigeon as wanting them altogether. Fig. 

 7. of Plate 111. exhibits their appearance in the elove. 



The carnivorous birds of all others have the coeca of the 

 fmallcft dimenfions ; fo much fo, in many iuftances, that 

 their exiftence has been often denied. Fig. 8. of Plnfe III. 

 is copied from the Memoirs of the Royal Academy of Paris ; 

 it fliews the (light dilatation which was found in the l>a/el 

 tuzzarcl ff^lio Imli^lus, Linn.) in place of tlx; ccecal pro- 

 ceflcs. On the internal fide, however, this enlargement was 

 furniflied with a valvular membrane, by which a pouch was 

 formed on e£ch fide. 



The owl appears a very remarkabl(Lexception to the com- 

 mon ftrufture of the acapitrcs, with refpeft to the formation 

 of the cceca, which both in figure and magnitude arc fimilar 

 to thofe parts in the gallinie. It is di£6cult to account for 

 this Angularity, unleis it be fuppofed neceffary to receive the 

 indigeftible parts of the animals, which this bird fwallows 

 cntir^. 



Some of the pl/clvorous birds, as the heron, &c. have only 

 one ccecal procels ; it is very (hort, and in the h;roii termi- 

 nates in a pointed manner. See Plate III. Jig. 9. 



There arc iuftances of the coccal appendages being alto- 

 gether wanting. They have not been found in the cajo- 

 KL'jry, the cormorant, the bittern {ardeajlcllaris), the parrot, 

 and the <wood-pecker. 



That portion of the inteftinal canal which correfponds to 

 the colon and reftum of mammalia, as already obferved, is 

 very fiiort in birds. In its external charafters, it refembles 

 the reft of the inteftinal canal, of which it appears to be 

 fimply the continuation. The internal furface is provided 

 with villi, which, however, are not fo long and delicate as 



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thofe of the fmall inteftines. They are rather very minute 

 eminences tlan villous proceftes, efpecially towards the ter- 

 mination of the reftum, at which place they often aifume a 

 decided granular appearance. 'I'he inner furface of the rec- 

 turn in the Neiv Holland ojlrich, however, prefents an excep. 

 tioii to this obfirvation ; it is covered with fine and truly 

 hair-like procelfes ; in this bird alfo the internal coat of tiie 

 great iuteiline is flightly folded or wrinkled tranfverfely, in 

 a manner fomewhat fimilar to the valvuls conniventcs of the 

 fmall inteftines of the human fubjcft. 



The termination of the reftum in birds is very ufually 

 called the cloaca, on account of its receiving, as a common 

 fink or fewer, both the excrements of the inteftines and the 

 urine. There is at this place a dilatation of the gut, which 

 is often only a flight and gradual enlargement juft within the 

 margin of the anus; but fonietimes it Iwells out fuddenly 

 iuto a pouch or fack. A remarkable example of which oc- 

 curs in the parrot ; fee Plate IV. in the Anatomy of Birds, 

 Jig. I. a the reftum, b the pouch. 



The cloaca of the bijlard has been found large enough 

 to contain an egg. It is of an oval form ; it is fituated 

 about an inch from the anus, and the reftum again expe- 

 riences a contraftion previous to its termination in the vent. 

 See Jig. 2. of Plate IV. in the Anatomy of Birds ; a, the rec- 

 tum before it enters the pouch ; b, b, the pouch laid open to 

 expofe its interior ; c, the contraftion within the anus. 



In the ojlrich, this ddatation is of great fize ; being capa- 

 ble of receiving one's two fifts, according to the report both 

 of the anatomifts of the French academy, and of Mr. War- 

 ren, who publiftied a difleftion of this bird, in the Philofo- 

 phical Tranfaftions, fee N° 394. p. 113. 



The ufe which the anal pouch anfvvers is almoft too ob- 

 vious to be mentioned, which is that of a temporary accom- 

 modation to the excrements of the bird, by which their ejec- 

 tion is rendered lefs frequent. 



The cloaca is furnifhcd with fomewhat ftronger mufcular 

 fibres than the reft of the inteftine, and is invefted with a re- 

 fleftion of cuticle, which in the larger birds is very palpable. 

 Connefted with the cloaca, there is a bag, or purfe, which, 

 taking the nanfie of the anatomift who firft delcribed it, is 

 called burfa Fabricii. 



The purfe of Fahriciiis is ufually of an oval or round 

 figure, deprelTed on the anterior and pofterior fides, and 

 thence always appearing empty. It i; furniftied with a nar- 

 row procefs, or neck, which is moft contrafted about its 

 middle. Its fituation is en the back part of the cloaca, to 

 which it is clofely connefted, being inclofed in the fame re- 

 fleftion of peritoneum which envelopes the reftum. When 

 the peritoneum is dilTefted off, it is found to be a diftinft bag 

 or fack, united only to the reftum by means of its neck, 

 which pafling obliquely in the coats of the cloaca, opens 

 into the inteftine by a (l;t-fliaped aperture. The internal 

 coat of the cloaca projefts over the opening like a pent- 

 houfe, and performs the office of a valve, readily allowing 

 the contents of the bag to pafs out, but flanding in the way 

 oi any regurgitation from the inteftine. See Plate IV. of 

 Jig. 2. and the purfe of Fabricius in the bufard, which is of 

 an oblong ftiape in this bird ; e, the flit by which it commu- 

 nicates with the cloaca. 



The fize of this bag is in general fairly proportioned to 

 that of the bird in which it is found. In the lujlard it has 

 been ftated to be two inches long ; in the goof; it meafures 

 about an inch and a quarter in length, and half an inch in 

 breadth ; and in the fparrow, it is about a quarter of an 

 inch long, and half as broad. 



The external fide of the burfa is fmooth and equal, but 

 the internal part is thrown into deep mgE. The folds are 

 di'pofed in an arborefcent form, and branch off with great 



regu. 



