.898 STRUCTURE AND CLASSIFICATION OF BIRDS 



The tongue and the roof of the mouth are covered with 



papillae. 



The provcntriculus has a patch of glands upon the right 

 side, heart-shaped in Eudyptes chrysocome and Spheniscus 

 demersus ; the gizzard is small and not gizzard-like. In 

 Pygosceles the proventricular gland, however, is zonary, and 

 the same state of affairs was found in one of four examples 

 of Aptenodijtes. 



In Eudyptes chrysocome the gut is thrown into a vast 

 number of primitive irregular folds. The duodenal loop is 

 excessively complicated, more so than in Haliaetus, to which 

 it bears some (probably a convergent) resemblance. 



The following are the intestinal measurements of a series 

 of species : 



From these data, which are extracted from WATSON'S 

 memoir already referred to, it is clear that there is some 

 individual variation in the length of the small intestine 

 among the penguins, which is, indeed, greater than anything 

 that has been recorded in any other group of birds. That 

 the ca3ca are so small is a curious fact in the structure of a 

 fish-eating bird. 



In the liver the right lobe is larger than the left in all 

 species. The gall bladder is large and extends a long way 

 down the abdominal cavity, as in the toucans. 



The syrinx is not especially divergent in structure. The 

 trachea has a septum down the middle, as in certain 

 petrels (q.v.) The intrinsic muscles are attached to the 

 tracheal rings a considerable distance above the bifurcation 

 of the tube, the distance varying from species to species. 

 There is but little fusion between the last rings of the 

 trachea. In Eudyptes chrysocome there is a thick fibrous 



