GIZZARD OF BIRDS. 163 



mon aperture ; and they are disposed in two compact oval masses, 

 one on the anterior, the other on the jiosterior surface of the 

 cavity. In the Heron {^Ardea cinereci) the solvent glands are of 

 more simple structure, and are more dispersed over the proven- 

 triculus ; but still they are most numerous on the anterior and 

 posterior surfaces. In the Flamingo the gastric glands are short 

 and simple follicles, arranged in tAvo large oval groups, which 

 blend together at their edges. 



The Natatores present considerable differences among them- 

 selves in the disposition of the solvent glands. In the Cormorant 

 {Plialacrocorax carbo) they are arranged in two circular spots, 

 the one anterior, and the other posterior ; while in the closely 

 allied genus Sida, or Gannet, they form a complete belt of 

 great width, and consequently are extremely numerous. In this 

 respect the Gannet, or Solan Goose, shows a nearer affinity to 

 the Pelican. 



In the Sea-Gulls the gastric glands form a continuous zone ; 

 and in the Little Awk (^Alca alle) they are spread over a great 

 proportional extent of surface, and the form of the digestive 

 organs is peculiar. The proventriculus is continued from the 

 oesophagus, -with very gradual enlargement, below the liver, and 

 is then bent up to the right side, and terminates in the gizzard. 

 The solvent glands are situated at the anterior or upper part of 

 the cavity everywhere surrounding it, but lower down they lie 

 principally upon the posterior surface, and where it is bent 

 upward toward the right side they are entirely wanting. In the 

 graminivorous lamellirostral Water-birds, as the Swan, Goose, 

 &c., the gastric glands have a simple elongated exterior form, but 

 have an irregular or cellular internal surface : they are closely 

 arranged so as to form a complete zone. 



In general the muscular or pyloric division of the stomach 

 called 'gizzard' {cjigerium, ventriculus hidhosus), immediately 

 succeeds the glandular or cardiac division ; but in some Birds, as 

 the Awk and Parrots, there is an intervening portion without 

 glands. 



The gizzard is situated below or sacrad of the liver, on the left 

 side of the abdomen, generally resting on the mass of intestines. 

 In the Owl the aizzard adheres to the membrane covering; the 

 internal surface of the abdominal muscles ; but in most Birds it 

 has a more dorsal position. 



In all Birds the gizzard forms a more or less lengthened sac, 

 having at its upper part two apertures ; one of these is of large 

 size, communicating with the proventriculus, figs. 83, 84, a, the 



51 2 



