298 



REPTILIA. 



smooth, or nearly so, like the first ; but the 

 communication between it and the third is 

 always very narrow. Generally speaking, 

 every arrangement seems to have been made 

 to retard the passage of alimentary substances, 

 and of the residue of digestion ; or at least to 

 prevent their passage from being too much 

 accelerated by the act of creeping, and the 

 contractions of the abdominal muscles ne- 

 cessary for its performance. The lining 

 membrane of the small intestine is thrown 

 into longitudinal folds of variable breadth, 

 and more or less thick and numerous, which 

 extend throughout its whole length, but 

 which sometimes are connected together by 

 transverse bands, so as to form cells. Some- 

 times these folds are beautifully fringed in the 

 first portion, so as to give the mucous lining 

 a villous appearance ; and they have been 

 observed quite white, with chyle filling their 

 lacteal vessels. 



The liver of reptiles is but indistinctly di- 

 vided into lobes, and frequently is only irre- 

 gularly notched upon its free border. Its 

 relative size, in this class of animals, is very 

 considerable. When the body is broad, it 

 occupies a large proportion of both the hy- 

 pochondriac regions ; but when the body is 

 elongated, it is situated in the right hypo- 

 chondrium only, but extends very far back 

 by the side of or beneath the intestines, in 

 which position it is maintained by folds of 

 peritoneum, resembling those which form the 

 air-cells of birds. 



In the Chelonians the liver is divided into 

 two rounded irregular masses ; one of which 

 fills the right hypochondrium, whilst the 

 other, which is connected with the smaller 

 curvature of the stomach, extends into the 

 epigastric and left hypochondriac regions : 

 these two divisions are only connected to- 

 gether by two narrow processes, which bound 

 a space through which the principal hepatic 

 vessels pass. 



In the crocodiles, whose digestive organs, in 

 many respects, resemble those of birds, the 

 liver consists of two distinct lobes, united to- 

 gether by a narrow central portion. 



In the spectacled Caiman (Crocodilus sole- 

 raps'), the right lobe is the largest, whilst the 

 left is small and triangular. These two lobes 

 separate anteriorly to receive the heart. The 

 gall-bladder is always connected with the 

 right lobe, but is here quite detached and 

 separate from it, a circumstance which holds 

 good likewise in the Gavials ; whilst in the 

 Crocodile it is closely connected with the 

 right lobe. 



Among the Lacertidte, the monitors have 

 likewise two lobes to their liver, which are 

 separatd by a deep fissure. In the safe- 

 guards (Ameiva) this fissure is less decided, 

 and the right portion of the viscus is prolonged 

 backwards to a long, narrow, pointed appen- 

 dage. This form conducts us gradually to 

 the shape of the liver most generally met 

 with in other Saurians, in which the organ 

 consists of a single mass, rarely divided by 

 deep fissures, but slightly notched at its mar- 



gin. This mass is generally of a triangular 

 shape, which is lengthened out in accordance 

 with the form of the body, sometimes ex- 

 tending backwards quite to the posterior 

 boundary of the abdominal cavity. In the 

 Ophidian reptiles the liver is not divided into 

 lobes, but forms a long cylindrical mass. 



The gall-bladder is, in the Chelonian rep- 

 tiles, almost entirely imbedded in the right 

 lobe of the liver, and is generally of very 

 great size ; whilst in the Saurian reptiles 

 it is generally situated at the bottom of the 

 fissure which separates the two lobes. In 

 the Ophidian reptiles, the position of the 

 gall-bladder varies ; in the genera Anguis, Am- 

 phisbcema, and Cecilia, it is more or less in- 

 crusted by the substance of the liver; but, 

 in the true serpents, its position is very 

 remarkable, for it is not only entirely se- 

 parated from the liver, but is removed to 

 a considerable distance from that viscus, and 

 placed in the immediate vicinity of the pylorus. 



In all reptiles the bile is conveyed into the 

 gall-bladder by the branches of the hepa- 

 tic ducts, which open either into its fundus, 

 its neck, or into the commencement of the 

 cystic canal : in the Chelonians, a very 

 large proportion of the bile would seem to 

 pass through the gall-bladder. In the Tor- 

 toises, which have the gall-bladder imbedded 

 in their liver, the hepato-cystic vessels open 

 immediately into its cavity. In the Emydes, 

 the hepatic ducts unite to form a canal, which 

 joins the neck of the gall-bladder. 



Amongst the Crocodiles, the spectacled 

 caiman has its bile-ducts arranged almost in 

 the same manner as in birds ; the right hepatic 

 canal opening immediately into the gall- 

 bladder. 



In the other Saurians, and also in Ophidian 

 reptiles, the hepatic duct unites with the 

 cystic, so that the gall-bladder is filled by the 

 reflux of the bile; generally, there is only one 

 hepatic duct, but in other cases there are 

 several, which enter the cystic duct near the 

 neck of the gall-bladder, as, for instance, in 

 Trigonocephalus. 



The pancreas is present in all reptiles, and 

 is generally situated close to the point where 

 the stomach terminates in the intestine, to 

 which it is most generally adherent. In the 

 Chelonians its shape is irregularly triangular, 

 being narrow and thin in the vicinity of the 

 pylorus, broad and bifurcated at its opposite 

 extremity, by which it adheres to the spleen 

 and to the large intestine. In the Saurians it 

 is generally placed close to the pyloric por- 

 tion of the stomach, and is divided into two 

 branches, one of which accompanies the biliary 

 canal ; the other adheres to the spleen. These 

 two branches unite in the vicinity of the 

 pylorus, and furnish a duct which opens into 

 the intestine along with that of the gall-bladder, 

 which not unfrequently is imbedded in the 

 substance of the pancreas. A similar dis- 

 position occurs in all the Ophidian genera. 



The spleen is in the Reptilia always present, 

 but its relations with the stomach are by no 

 means so constant as in birds and Mammalia. 



