REPTILES. 



in the ophidians ; for example, when the latter is not dif- 

 tonded with food, becaufe its parietcs contraA fooncr after 

 enlargement than thofe of the oefophagus. The membranes 

 are the fame in both, and, when the tube increafes in fiz.e 

 infcnfibly to the ftomach, it is often very difficult to aflign 

 the limits of the two parts, and confcquently the fituation 

 of the cardia. Tlie llomach is generally without any cul- 

 de-fac, oval and elongated : its parietes ufually thia. The 

 mufcular coat is then hardly perceptible, at leaft in fome 

 part of its extent, and the cellular is confounded with the 

 mucous or internal. The pylorus is ufually without any 

 valve ; it is marked by a fimple contraftion, by the ^rreater 

 thicknefs of the parietes of the llomach, and by the different 

 ilrufture of the inteftinal membranes. 



In the turtle, the internal furface of the oefophagus is 

 befet with long, hard, conical papillx, of which the points 

 are direded backwards, with the effed, apparently, of pre- 

 venting the return towards the mouth of the matters fwal- 

 lowed by the animal. Such, at leaft, is the notion generally 

 entertained of the end or purpofe of this fti-udlure. But the 

 abfence of fuch provifion in all other animals where the ne- 

 ceffity feems equally to exift, cannot but render us fceptical 

 on the fubjeft, more particularly as we know no fads con- 

 cerning the nature of the food, the mode of its deglutition, 

 nor any peculiar modification of furrounding or conneded 

 organs, to which this fingular llrudurc might be fuppofed 

 to bear fome relation. The llomach is gradually dimi- 

 nifhed in fize from the cardia to the pylorus : it is bent on 

 jtfelf, and the portion beyond the curvature is thicker than 

 the reft, in confequence of the mufcular fibres being more 

 copious. The internal coat has longitudinal folds in this 

 part, but hardly any in the other. The fituation of the 

 cardia is well marked, and the oefophagus is diftinguilhed 

 from the ftomach by the fuddcn dilatation of tlie latter. The 

 pylorus has no valve. 



Among the faurians, the crocodile has a peculiarly (haped 

 ftomach ; it is very diftind from the oefophagus by its glo- 

 bular figure. Near the infertion of this canal there is fe- 

 parated from it below a fmall cul-de-fac, opening into the 

 mteftine by a very fmall orifice, and having its cavity fepa- 

 rated from the great fac of the ftomach by a kind of ftrait. 

 Confequently the general cavity of the ftomach is a large cul- 

 de-fac, of which the parietes are very thick. The internal 

 membrane forms confidcrable plaits arranged in a Terpentine 

 form, like the convolutions of the brain. The cellular coat, 

 which is not very diftind from the mucous in the oefophagus, 

 becomes more fo in the ftomach. The mufcular nearly 

 equals the two others in thicknefs ; the coats are altogether 

 much thinner in the fmall cul-de-fac. 



In the other faurians there is no cul-de-fac. The ftomach 

 is oval and very elongated in the iguana, witliout curvature ; 

 the oefophagus dilates gradu.-illy to form it. The only mark 

 that can guide us in determining the fituation of the cardia is, 

 the ceffation of the longitudinal folds of the internal cefo- 

 phageal membrane. The ftomach is fuddenly contraded, 

 and bent a little before its termination at the pylorus. Its 

 parietes become thick and opaque at fome lines from this 

 i^perture, from an mcreafe of the mufcular fibres, of which 

 thp tranfverfe are ftrongly marked. The internal opat forms 

 no fold ; there is no valve at the pylorus, which is very 



fmall. 



In the tupinambis monitor the ftomach forma a long tube, 

 bent into almoil a complete circle. 



In the Schneiderian fcmk we again meet with the fame 

 «k)ngated form, tranfparent parietcs, and difficulty of diftin- 

 guiftiing the ftomach from the oefophagus, except by the 

 ioniritudiiial folds of its inner membrane, and the thicknefs 



of its mufcular coat. But the pofterior part of the ftomach 

 contrads fuddeidy, is bent towards the right, and a little 

 elongated in this direction before it terminates. The pa- 

 rietes of the latter portion are more thick and opaque, and 

 its internal membrane is folded longitudinally. 



The ftomach begins by a fmall dilatation in the camcleon, 

 then it aftumes a cylindrical and elongated form, and is bent 

 on itfelf J it is conliderably contraded before it terminates, 

 and forms a fmall cylindrical canal, of which the internal 

 membrane is folded longitudinally. The mufcular coat is 

 thicker in this contraded part than elfewhere. It forms a 

 prominent ring at the pylorus. 



In the dragon the ftomach is fhaped like a pear, of which 

 the large end correfponds to the cardia ; it has no curvature ; 

 its parietes arc tranfparent ; they become thicker and opaque 

 near the pylorus ; and thefe charaders are the only circum- 

 ftance, by which we can diftinguifti it from the beginning of 

 the inteftinal canal, which has thin and tranfparent coats. 



The ilomach is alfo pear-ftiaped in the gecko ; the oefo- 

 phagus makes a curve before it ends, and is inferted at one 

 fide of the bafis. It is narrnw, with thick coats, a ftrong 

 mufcular covering, and broad longitudinal folds of the in- 

 ternal or mucous coat. The fides of the organ are thicker 

 at its extremities ; and the pyloric end is a little bent. The 

 internal membrane is fmooth. 



In the ophidian order the ftomach is (haped like an in- 

 teftine, hardly larger than the oefophagus, and without cur- 

 vature. The internal membrane is folded longitudinally. 

 When the ftomach is empty, thefe folds are thicker than 

 thofe of the oefophagus, which are not always obferved. 



The oefophagus of a fnake, examined by Spallanzani, 

 formed a cylindrical tube like an inteftine, for about nine 

 inches : it then became gradually narrower, fo as to con- 

 ftitute a funnel of the length of four inches and a half. This 

 funnel was the true ftomach. The fides of the ftomach 

 were thicker than thofe of the oefophagus : no glands or 

 follicles could be feen in the latter ; but the ftomach was 

 abundantly fupplied with them throughout its whole length ; 

 they difcharge part of their liquor on being prefled, and the 

 internal coat is moiftened with it. Diftertations relative to 

 the Natural Hiftory of Animals and Vegetables, v. i. 

 p. 1 12 and 1 13. 



In frogs and toads the ftomach is ftiaped nearly as in the 

 chelonian reptiles. At firft confiderably dilated in compari- 

 fon with the oeiophagus, it is gradually contraded, then 

 curved fo as to form an inteftine-like canal, with thick coats, 

 ending at the pylorus. 



It is nightly curved only near its pofterior extremity in 

 the falamanders. Its figure is elongated and not much 

 fwoln ; the parietes thick ; and the internal membrane ex^ 

 hibits fmall ruga. There is a fold near the pylorus, in the 

 fituation of the curvature. Figures of the ftomach and 

 inteftines of various reptiles are given in Cuvier's Legons, 

 pi. 41. 



Intejlinal Canal. — Its length, in proportion to that of the 

 body, is greatell in the mammalia, and diminifhes fucceffively 

 in birds, reptiles, and fifties. In reptiles it is often hardly 

 twice the length of the body, taken from the extremity of 

 the fnout to the anus. But tadpoles exhibit in this refped 

 a remarkable peculiarity. Their inteftinal canal is nearly 

 ten times as long as the fpace between the fnout and anus, 

 while in the frog it is not more than twice the length of the 

 correfponding fpace. Other important differences, which 

 will be noticed fubfequently, exilt in the two cafes. This 

 ftiortnefs of the alimentary canal correfponds to the nature 

 of the food in reptiles, which is derived from the animal 

 kingdom. 



The 



