DIGESTIVE ORGANS OF BIRDS. 



175 



&c.' ' My own observations show the liver to be relatively largest 

 in the less active aquatic and land birds, smallest in the birds 

 that fly best and breathe 

 most : compared in the li- 

 mits of the class the liver 

 seems to be developed in- 

 versely as the lungs and 

 their appendages, and so 

 far as it is associated -with 

 the luno's in eliminatino- 

 waste elements from the 

 blood, to have less to do in 

 that way, as the breathing 

 organs perform most. 



The liver, figs. 85, 87, 

 m, m, is situated a little above 

 the middle of the thoracic 

 abdominal cavity, with its 

 convex surface towards the 

 abdominal parietes, and its 

 concavity turned towards 

 the subjacent viscera: the 

 rio^htlobe covers the beo-in- 

 ning of the duodenal loop, 

 pancreas, and part of the 

 small intestines ; the left 

 lobe covers the proventri- 

 culus and part of the giz- 

 zard ; and the apex of the 

 heart is received between 

 the upper ends of these 

 principal lobes. The liver 

 is, as it were, moulded upon 

 all these parts, and presents 

 corresponding depressions 

 where it comes in contact with them. 



It is generally divided into two nearly equal lobes (^Raptor cfi. 



Tostcrior view of the liili.-iry ami rancrcatlc duct in the 

 Horul>iU. VI I- . 



^ Numljcr of times the weight of the liver in that of the bod}- :- 

 Cathartes atratus, 47; Chelonia caretta, 47: 

 Si/rnium nebulosum, 56 ; liana Catesbiana, 55; 

 Tantalus locniator, 64; Coluber guttatus, 64: 

 Meleagris gallopavo, 70; Alligator lucius, 73: 

 and see other cxanii)les, in ccxlv. p. 113. 



