REPTILES. 



(Gangetic crocodile), the large iiiteltine lias a pyriform 

 figure, the termination of the fmall being infertcd into its 

 broadell part. 



In the lizards, the reftum is cylindrical, and much broader 

 than the fmall intelline which is infcrted into it ; the latter, 

 after having turned forwards from the pylorus, is folded 

 backwardB, and proceeds in a tortuous direftion as far as 

 the reftum, which purfues a flriipjht courfe to the anus. The 

 parietes of the iuteilinal canal are thin and tranfparent ; the 

 internal membrane has folds arranged in a zigzag form. 



In the cairieleon, the coats of the inteftine have the fame 

 ftrufture ; the capacity of the fmall is not much inferior to 

 that of the ftomach and large intelline, in the greatell part 

 of its extent ; but it becomes much coiitrafted a little before 

 its infertion into the latter. There is no valve indicating the 

 feparation between the difl'erent portions ; the internal mem- 

 brane has waving folds, the loofe edges of wliich have a 

 fringed appearance ; they are diredled longitudinally, and 

 contratling as they approach the reftum, difappear at fome 

 dillance from that intelline, where the internal membrane be- 

 comes fmooth and without any folds. The mufcular coat 

 is thicker in the redlum than in the fmall intelline, where it 

 is indillindl. The cellular coat is not manifeft. 



In the dragon, the inteftinal canal forms two turns and a 

 half before it arrives at the anus ; the commencement is dil- 

 tinguifhed only by the different appearance of its coats, 

 which are much thinner than thofe of the ilomach. 



In the iguana, the parietes of the inteftinal canal are 

 thin and tranfparent, gradually contrafling from the pylo- 

 rus to the infertion of the fmall intelline into the rectum ; 

 the latter is of an elongated form, but contrafted at one 

 part, by which it becomes divided into two portions almoft 

 of a cylindrical (hape. The internal membrane has fome 

 folds direfted longitudinally in the fmall inteftine. In the 

 common iguana, which has the inteftinal canal long and very 

 capacious, there is a true cscum, diftinguiftiable from the 

 large inteftine by the greater thicknefs of its coats, and by 

 a partition feparating their cavities, fo that it is through a 

 very narrow orifice that the fecal matter pafles from the 

 CECum into the fucceeding part of the large inteftine. The 

 infertion of the fmall into the former takes place near its 

 middle. The coats of the caecum have in fome degree a fac- 

 culated form. The internal furface is fmooth and without 

 folds. In the large inteftine the internal membrane has the 

 fame ftrufture, except at the commencement, where there are 

 found about fix tranfverfe valves, which do not extend around 

 the whole tube of the inteftine. In the fmall inteftine there 

 are longitudmal folds. The pouch formed by the cicum 

 is about three-fourths of an inch in length, and twice as 

 fhuch in breadth. 



In the gecko a gouttelettes the parietes of the inteftine 

 are alfo tranfparent, the fmall has but little capacity, but 

 IS unequal at different parts ; it is inierted into the centre of 

 the firil portion of the large inteftine, which is of a globular 

 form ; and is feparated, by a contraftion in its coats, from 

 the fecond portion, which is elongated and oval, the fmall 

 extremity correfponding to the anus. In the Schneiderian . 

 fcink the thin and tender coats of the inteftinal canal are much 

 dilated at the commencement of the fmall inteftine, and con- 

 trafted at the part where it is introduced into the large. 

 We have already mentioned that it is dilated into the form of 

 a bladder, and enveloped by the firft portion of the large 

 inteftine, fimilarly dilated. The excrements, which pafs 

 through the fmall aperture in the velicular dilatation of 

 the fmall inteftine, find their way partly into the interval 

 between the latter and the internal furface of the large. Be- 

 yond the firlt portion the redlum becomes cylindrical. The 



fmall inteftine is divided into many pouches by contraftionj 

 which pretty nearly correipond to its different turns. 



In the ophidian order the inteftinal canal purfues a fer- 

 pentine direftion as far as the reftum, and preferves nearly 

 the fame diameter throughout, dilating but little in the 

 large inteftine. In the fmall, the internal membrane form, 

 broad longitudinal layers, folded in the manner of ruffles ; it 

 is rugous, and in the reftum forms thick, irregular folds, 

 which are continued to the anus. In the coluber natrix, 

 according to Blumenbach, the whole length of the intefti- 

 nal canal does not equal that of the animal. The fmall in- 

 telline forms a very confiderable valve at its entrance into 

 the large. Lib. cit. p. 174. 



In the falamanders, the fmall inteftine is very narrow in 

 companion with the reftum, where the internal membrane 

 forms thick and fimbriated folds. In toads and frogs, 

 we find a nearly analogous conformation and itrufture, there 

 being only a flight variation in the form of the reftum, 

 which is more or lefs of a conical or pyriform fhape, as in 

 many frogs, or cylindrical, as in toads. But in the tadpoles 

 of both, the inteftinal canal is altogether very different from 

 that of the fame animal in the perfedt ilate. Long, narrow» 

 and nearly of uniform diameter in the fmall intelline, mak- 

 ing irregular turns in its courfe, its volume augments at the 

 reftum, which becomes of a facculated form, and makes 

 two fpiral turns upon itfelf, before it proceeds to tlie anus. 

 There is no valve feparating the two portions of the in- 

 teftine. 



In the firen lacertina the inteftinal canal proceeds almoft 

 in a ftraight courfe from the pylorus to the anus, making but 

 one fmall turn near its middle, from which it proceeds ftraight 

 to its termination. Its coats are tranfparent, and its diame- 

 ter nearly equal throughout, not admitting of any divifion 

 into fmall and large inteftines. 



Phylwlogy of the digejll've Or^anj.— Blumenbach afferts 

 that moll reptiles are omnivorous, while fome are confined 

 to one fpecies of food, as the bufo or rana calamita, which 

 feeds on a few fpecies only of infefts, and tliofe ahvc. (Spe- 

 cimen Phyfiol. Comp. p. 29. ) We cannot help doubting the 

 accuracy of the firft part of this flatement ; the foodfeems 

 to us almoft entirely animal. Serpents, frogs, and lizards, 

 live on the fmaller animals or infefts ; and even the turtles, 

 which eat particular kinds of marine plants, feed alfo on 

 the moUufca. The fimple ttomachs, the fimple and (hort 

 alimentary canals of the whole order, correfpond very clearly 

 to what we underftand concerning their carnivorous habits. 

 Newts feem to care for living infefts and worms only, which 

 they feize with their jaws, and fwallow whole. 



Two apparently contradift ory circumllances have been 

 noticed in this order ; great voracity in many inllances, but 

 in all a wonderful power of abftinence. Salamanders fome- 

 times devour their own excrement, and earth. Serpents 

 often take in a quantity of food, which diftends their bodies 

 inordinately, and leaves them inaftive, and hardly capable 

 of motion. The falamanders will fometimes fluff them- 

 felves to fuch a degree with worms, that they crawl up 

 again out of their ftomachs. See Spallanzani's Differtations, 

 vol. i. p. 1 10. 



" A newt," fays Bonnet, '■' having devoured a large earth- 

 worm, I fupplied it with another above four inches long, 

 and thick in proportion. It immediately fwallowed the 

 whole, except a line or two that hung out of the mouth ; 

 but the worm was foon throvirn up, and the fame repeated 

 twice, but the worm ftill lived." Spallanzani's Trafts, 

 vol. ii. p. 366. 



The inftances which are recorded of the abftinence of 

 reptiles feem at firil almolt incredible. Not to mention the 



toads. 



