392 ORGANS OF DIGESTION. 



vertebrata. The liver, the spleen, the pancreas, the kidneys, 

 and the testes and ovaria present the same longitudinally 

 extended form which is seen in the oesophagus, the stomach, 

 and other parts of the alimentary cavity of the ophidian rep- 

 tiles, and in the whole conformation of their trunk. The 

 convolutions of the small intestine are not bound together in 

 a sheath, but float freely, attached to the mesentery in the 

 aquatic species of serpents, and in some of the higher sauroid 

 forms, as the anguis. The large intestine is often sacculated 

 by transverse constrictions approaching in form to valves, 

 which divide its cavity, and still further delay the passage of 

 the food through the ever active trunk of these animals. The 

 liver is generally of a lengthened cylindrical form, not divided 

 into lobes, provided with a distinct gall-bladder, and sends its 

 secretion into the duodenum, near to the pyloric valve, where 

 also terminate the several ducts from the lobes of the pan- 

 creas, which continue separate to their termination in the 

 intestine, and the small spleen is here often compactly united 

 to the pancreas by vessels and its peritoneal sheath. 



The saurian reptiles are mostly carnivorous, like the serpents, 

 and swallow their prey undivided, and they present a corres- 

 ponding short and simple alimentary apparatus ; but as their 

 trunk is shorter, and their abdomen is not habitually pressed on 

 or dragged along the ground, they do not present the longitudi- 

 nally extended form of the viscera, nor the modifications de- 

 signed to protect the organs and check the rapid transit of the 

 food, which w observe in the ophidian reptiles. The teeth 

 are still merely prehensile organs, sharp, conical, recurved, 

 similar in form, and placed alternately ; but they are more 

 fixed in- their attachment by the outer alveolar margin of the 

 maxillse and by the gums; sometimes they are lodged in 

 deep osseous alveoli, and are generally restricted to a single 

 row along the margin of the jaws. Small teeth, in a few 

 species only, are found also in the pterygoid bones, as in 

 serpents ; and, as in them, the tongue is generally long and 

 bifid, and the salivary glands very imperfectly developed. 

 The oesophagus, like the neck, is short and wide, and com- 

 monly leads to a narrow elongated stomach, placed from left 

 to right, with its cardiac and pyloric orifices at the opposite 



