472 ON OPISTHOCOMUS CRIST ATUS. 



at this stage of its existance the parents feed it by pass- 

 ing the contents of its own crop into that of its young. 



When the neck is stretched out , the intestinal tract is 

 four times the length of the bird. 



The liver is large and well developed and covers the 

 stomach. 



The kidneys have two ducts which enter the cloaca near 

 its outer orifice. 



The wind-pipe after it enters the chest gives off on 

 each side one small branch , and passing on terminates 

 into two tubes (fig. 6). 



In the adult the crop is one quarter the size of the body. 

 It is covered with a coat of red muscular fibres that pass 

 upwards along the upper oesophagus and downwards along 

 the second oesophagus making the latter alternately con- 

 tracted and dilated and at the same time giving it a wavy 

 appearance, until it reaches the stomach. 



The second oesophagus fills half the cavity of the chest, 

 and keeps the same diameter throughout until it becomes 

 stomach when it contracts. The stomach is small, smaller 

 in diameter than the second oesophagus , and has a thin 

 red muscular cap on its right extremity. In the young fledg- 

 ling the crop and stomach are the same size , while in 

 the adult the stomach is the size of the intestinal tube , 

 in fact the old bird has no stomach at all. 



The liver has two lobes and no gall-bladder. 



Both jaws have a row of tubercles on their inner mar- 

 gin that act as teeth. The lachrymals are anchylosed to the 

 nasals. The coracoids , clavicles , and sternum are united 

 into one piece ; the sternum is keeled , and bevelled at the 

 expense of the keel forwards , and has two small notches 

 on each side ; the two clavicles are united anteriorly and 

 unite with the breast-bone through a long thin plate; their 

 plain is almost parallel with the spine , and so affording 

 a resting place for the enormous crop. The ribs are broad 

 and flat. The head of the fibular assists in the formation 

 of the knee-joint and is not fused with the tibia. The 



rsTotes from the I^eyden JMuseum, Vol. X. 



