AUXILIAKY SECRETIONS. 725 



the tongue is lubricated are of very considerable size. They pass 

 further back than the angle of the lower jaw, extending even to be- 

 neath the occiput ; and their secretion, which is viscid and tenacious, 

 enters the mouth by a single orifice situated under the point of the 

 tongue. 



(2055.) In the generality of birds, however, there is only one pair of 

 salivary glands; and these, in many cases, seem to be united into a 

 single mass, separated posteriorly into two lobes, and situated beneath 

 the palatine membrane, behind the angle of the rami of the lower jaw. 

 From these glands a thick, white and viscid fluid is poured into the 

 mouth through numerous orifices, principally disposed along the mesial 

 line which separates the two glands. 



(2056.) We have already spoken of the gastric glands which densely 

 stud the coats of the proventriculus, and furnish the " gastric juice," 

 and therefore pass on to notice the other subsidiary chylopoietic viscera, 

 namely, the liver, the pancreas, and the spleen. 



(2057.) The liver is a viscus of considerable magnitude, consisting of 

 two principal lobes, and firmly suspended in situ by broad ligaments and 

 membranous processes. The vena portce, supplying that venous blood 

 from which the bile is elaborated, is formed by vessels derived from 

 numerous sources, receiving not only the veins of the stomach, spleen, 

 and intestines, as in Mammalia, but likewise the renal and sacral veins, 

 another proof, if any were wanting, that no arrangement by which the 

 decarbonization of the blood can be facilitated has been omited in the 

 organization of the class before us. The hepatic arteries and the hepatic 

 veins present nothing remarkable in their disposition; but the course of 

 the bile from the liver into the intestine merits our notice. Two sets 

 of ducts are provided for this purpose : the first (fig. 359, i) carries 

 the bile from the liver into the gall-bladder (#), from which another 

 duct conveys the bilious fluid into the duodenum ; but the second set of 

 bile-vessels conducts the secretion of the liver at once into the intestine, 

 by a wide canal (o) that has no communication whatever with the 

 gall-bladder. There is, therefore, no arrangement like that of the 

 " ductus communis choledochus " of Mammals : if the bile is wanted im- 

 mediately, it passes at once into the intestine through the duct o ; but 

 if digestion is not going on, it is conveyed into the gall-bladder through 

 the duct i, to be there retained until needed. 



(2058.) The pancreas (fig. 359, e e) is a conglomerate gland of con- 

 siderable size, situated in the elongated loop formed by the duodenum : 

 it generally consists of two portions more or less intimately connected, 

 and from each portion an excretory duct (n) is given off; these two 

 ducts terminate separately in the intestine, in the immediate vicinity of 

 the openings of the biliary canals. In some birds even three pancreatic 

 ducts are met with, as is the case in the common Fowl ; but under such 

 circumstances the third duct, instead of opening into the intestine at 



