REPTILES. 



The following table of the length of the intcftinal canal in various reptiles, is taken from the third volume of Cuvier'a 

 Lemons d'Anatomio comparee, p. 457. 



* In a co'^moii fnake of four feet in length, Blumenbach 

 found the inteftinal canal about three feet, nearly llraight, 

 or at leaft very fligiitly undulatcil .- its proportional length 

 was therefore different from that exprelied in the table. 

 Specimen Phyfiol. Comp. p. 30. 



The inteftinal canal of reptiles has in general no appendix 

 to mark its divifion into large and fmall intellincs ; this divifion 

 exids neverthelefs in moil of them. All the chelonian.i, moll 

 of the faurians, the ophidians, and the batracians, with the 

 exception of the fuen lacertina, have a long and flender in- 

 telline, inferted into a large and fhort intelUne, and com- 

 monly prolonged into the cavity, fo as to form a circular 

 margin of a valve-like form. The fides of the large intef- 

 tine are almoit always thicker and ftrongcr than thofe of 

 the fmall. Tiie membranes differ too ; the mufcular in re- 

 fpeft to its longitudinal fibres, and the internal in its folds. 

 The iguana is the only aiTimal of this clafs, in which a true 

 cscuiri has been noticed. 



0/ the Intcjllnal Canal. — All reptiles have the inteftinal 

 canal very fliort, but not of the fame diameter in its whole 

 length. In the firft and moft confiderable portion, tlie ca- 

 pacity is much inferior to that which it is found to poilefs 

 near its termination ; fo tliat it may be divided, as in the 

 mammalia, luto fraall and large inteftines. A circular valve 

 is moft frequently found feparating the two divifions ; it is 

 formed by a prolongation of the fmall inteftine, which be- 

 comes dilated, and fometimes is extended into a kind of fac, 

 projefting more or lefs into the cavity of the large inteftirie, 

 and rendering tlie parietes double at that part. It is thus 

 found in the fcJchneiderian fcink. 



In tortoifes, the diameter of the fmall inteftine gradually 

 diminlfhes from the pylorus to the point of its infertion into 

 the large : the area of which is four times greater than tliat 

 of the fmall, and its parietes have the fame Itrufture as in 

 the other reptiles. The cavity is regular throughout, there 

 being no partial dilatations or facculi. The internal mem- 

 brane has folds, more or lefs broad, and of a membranous 

 llruclure, in different fpecies, fometimes conneifted in a re- 

 ticular form at the commencement of the fmall inteftine, 

 having a longitudinal and parallel direction in the reft of its 

 extent, and arranged more or lefs irregularly in the large. 

 The large inteftine proceeds in a ftraight direction to the 

 anus, whilft the fmall makes many irregular turns in its 

 «mrfe. 



Blumenbach found the inteftinal canal of the hawk's-bill 

 turtle (teftudo caretta) five times as long as the whole ani- 

 mal. The (mall inteftine, as it is called, was larger than 

 the ftiort portion of the large inteftine ; the wliole internal 

 furface was covered internally with an abundance of mucus. 

 Syft. of Compar. Anat. p. 173. 



The internal coat of the inteftine of the turtle is covered 

 with innumerable thin longitudinal procelies, lying clofe to- 

 gether, and increafing the furface of the gut to a vaft ex- 

 tent. They are moft numerous in the upper part of the 

 canal, and gradually diminidi in number, until they ceafe al- 

 together, below. In the latter relpe«it they refemble the 

 valvula; conniventes of man, and the villi of all animals. 

 For thefe ftruAures are always moft diitinft at the com- 

 mencement of the canal, where abforption goes on to the 

 greateft extent. The alimentary matter is deprived more 

 and more of its nutritious parts, as it defcends in the intef- 

 tine ; and hence a lefs extenfive abforbing furface is fuffi- 

 cient, in the lower part of the canal, for taking up the re- 

 mains of really nutritious particles. Yet Blumenbach fays 

 that he found thefe folds fo numerous in the rcftum of the 

 hawk's-hill turtle, that a feftion of the gut refembled a 

 broad radiated band. Lib. cit. p. 173, note. 



In the crocodile of the Nile, the linall inteftine may be 

 diltinguiftied into two portions, the one more capacious, 

 having thinner coats, and making lour turns in fuch a man- 

 ner as to form four permanent angles ; tliL- other, more con- 

 tratfted and having thicker parietes, inclofes between its in- 

 ternal and mufcular coats a layer of glandular fubftance, 

 femi-tranfparent, of a grey colour and pulpy confiftence. 

 In the internal membrane lining the ghandular lubftance, 

 there are feen longitudinal folds arranged in a zigzjg form, 

 and connetted together laterally, by lu^aller folds, fo as to 

 form a reticular furface. In ttie firft portion of the fmall 

 inteftine, where the glandular fubftance is not manifeft, the 

 folds arranged in a zigzag form are replaced by fine villous 

 eminences. Near the termination of the imall inteftine there 

 are only feen fome waving folds, connected by a few, pro- 

 ceeding tranfverfely. In the large inteftine, the folds are 

 arranged irregularly, forming a velvet-like furface. 



The form of the rcftum (under which term is included 

 the large inteftine of filhcs and reptiles) is cylindrical in the 

 crocodile of the Nile ; and the fmall inteftine, where in- 

 ferted into it, is nearly of equal diameter. In the gavial 



(Gangetic 



