ANIMAL BIOLOGY. 



[Part I. 



lines in the figure : both start from the right lobe of the liver, 

 the shorter entering the duodenum near the gizzard, the other 

 in the distal limb of the loop. The liver itself is a large reddish 



brown mass, with a right and 

 left lobe, hollowed on its dorsal 

 surface for the reception of the 

 gizzard and duodenum. There 

 is no gall bladder. Following 

 on the duodenal loop is a 

 short loop of jejunum beginning 

 at Je. ; and on this, in turn, fol- 

 lows the ileum, of which the 

 proximal part forms a coil (/'/.), 

 and the distal part a single 

 loop (il\). The junction of the 

 small and large intestines (or 

 rectum, rm.) is marked by two 

 small cceca (cce.). The rectum 

 opens into the cloaca, at the 

 dorsal side of which is, in young 

 birds, a glandular oval sac, the 

 Bursa Fabritii (B. F.) An inch 

 or so of the small intestine 



Fio. 20. VISCERA or PIGEON. 



. F. Bursa Fabricii. cce. Csecum. d. ap. 

 Cloacal aperture, d d Positions of two of 

 the pancreatic ducts. Du. Duodenum, g. 

 Gizzard, il. il\ Loops of ileum. Je. Jejunum. 

 Pn. Pancreas. Prov. Proventriculus. rm. 

 Rectum. Tr. Trachea. 



SO 



should be cut out and slit 

 open under water. It will pro- 

 bably contain a semi - fluid 

 pulpy substance, the chyme. 

 The inner walls will be velvety 

 in appearance, from numerous minute processes termed villi. 



2. The Respiratory System. No definite epiglottis guards the 

 glottis which opens into the trachea, at the anterior end of which 

 is the larynx. There are, however, no vocal chords, and this 

 organ is not in birds a functional organ of voice. The trachea 

 is strengthened with bony rings, and at its lower end, just before 

 it forks to send a bronchus to each lung, some of the lower 

 tracheal rings are united together to form a kind of box, the 

 syrinx, which is the organ of voice in birds. 



