DIGESTIVE ORGANS OF REPTILIA. 691 



Crocodile is the connecting link between REPTILES and BIRDS, and in 

 almost every part of its body it presents a type of structure almost in- 

 termediate between the two. 



(1929.) The stomach of this creature (fig. 339) might, in fact, be 

 almost mistaken for the gizzard of a rapacious bird. The oesophagus (c) 

 terminates in a globular receptacle, the walls of which are very mus- 

 cular ; and the muscular fibres (a) radiate from a central tendon (6) pre- 

 cisely in the same manner as those of a bird. The pyloric orifice is 

 closely approximated to the termination of the oesophagus, and the 

 commencement of the duodenum dilated into a round cavity (d), an 

 arrangement which, as we shall see in the next chapter, exactly 

 resembles that met with in the feathered tribes. 



(1930.) In the neighbourhood of the pylorus, the walls of the stomach 

 in all the Reptilia become perceptibly thickened; the intestine is 

 generally short, and usually divided into two portions, representing the 

 small intestines and the colon, the division between the two being 

 marked by a prominent valve analogous in function and position to the 

 ilio- colic valve in the human subject ; and sometimes, moreover, as for 

 instance in the Iguana, there is a distinct caecum developed at the com- 

 mencement of the large intestine. 



(1931.) The auxiliary secretions subservient to digestion in the class 

 before us are the salivary, the hepatic, and the pancreatic. 



(1932.) The salivary glands are of very peculiar construction *. In 

 the CHELONIAN, the SAURIAN, and the BATBACHIAN orders, the substance 

 of the tongue seems to be principally made up of a thick glandular 

 mass, formed by a multitude of little tubes united at their bases ; but, 

 becoming separate towards the surface of the tongue, they give the whole 

 organ a papillose or velvety appearance. This glandular apparatus rests 

 immediately on the muscles of the tongue, and upon its sides a multitude 

 of pores are visible, through which the salivary secretion exudes. 



(1933.) In the OPHIDIAN REPTILES, from the manner in which they 

 swallow their prey, the bulk of the tongue is necessarily reduced to the 

 utmost extent ; the whole organ seems converted into a slender bifid 

 instrument of touch, and is covered with a delicate membrane. Instead 

 of the salivary apparatus described in the last paragraph, two glandular 

 organs (fig. 337, s s), placed immediately beneath the skin of the gums, 

 surround the margins both of the upper and lower jaws; and from 

 these an abundant salivary secretion is poured into the mouth, through 

 orifices situated externally to the bases of the teeth. 



(1934.) The liver of Reptiles (fig. 340, h) requires no particular 

 description : its secretion, as well as that of the pancreas (fig. 340, o), 

 is poured into the intestine in the usual manner, at a little distance 

 from the pylorus. 



(1935.) The spleen and system of the vena portce are disposed in the 



* Cuvier, Le9ons d'Aiiatomie Comparee, iii. p. 223. 



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