BIRDS. 339 



principal lobes connected only Ly a small strip, of wliicli that of the 

 right side is commonly the larger. It is attached to the sternum, the 

 stomach and the air sacs by duplicatures of the peritoneum, occupies 

 the upper region of the abdomen, and is for the most part covered 

 by the sternum. A gall-bladder is generally present, and is wanting 

 only in a few birds, namely, the ostrich, the pigeons, most species of 

 parrots, tlie toucans, &c. Also in some individuals it has not been 

 found, whilst it has been present in others of the same species. It 

 lies commonly between the two lobes of the liver and nearer to that 

 of the right side. From each of the lobes a gall-duct proceeds; 

 the two mostly unite to form a common duct which opens into the 

 duodenum, distinct from the duct of the gall-bladder. 



The pancreas is whitish red, elongate and large, and usually di- 

 vided into two lobes, often even double. Commonly it has two, 

 only seldom three ducts, which do not unite with the gall-ducts, 

 but open separately into the duodenum, partly in front of, partly 

 between these last-named ducts. The spleen is small, oval or 

 spherical, and lies far forward, close to the glandular stomach. 



With respect to the lymphatic system, lacteals are very nume- 

 rous in the intestinal canal. Those of the rectum and of the two 

 coeca are for the most part in connexion with the veins of the 

 pelvis 1; those of the small intestines form, with the lymphatics 

 of the rest of the viscera and of the hind limbs, a large plexus on 

 the arteria aorta and coeliaca ; from this arise two thoracic ducts, 

 each of which runs to the superior vena cava of its own side, and 

 empties itself there under the junction with the jugular vein, 

 having first received the lymphatics of the neck and of the wing. 

 Conglobate or lymphatic glands are not found in the mesentery; 

 hitherto they have been met with only in the neck and the upper 

 part of the thoracic cavity^. 



^ At the lower part of the pelvis there are in some birds (the goose, swan, casuary, 

 &c.) two small vesicular Ij-mphatic expansions on which Stannius observed muscular 

 fibres, but which were not seen to pulsate rhythmically, like the lymphatic hearts of 

 reptiles ; from these expansions a vein arises ; see them figured from the goose in 

 Panizza Observazioni antropo-zootomico-Jisiologiche, Pavia, 1830; fol. Tab. ix. figs. 3, 8 ; 

 compare Stannius in Mueller's Archiv, 1842, s. 449 — 452. 



^ Hewson first discovered and described the lymphatic system in birds, Pkilos. 

 Transact. Vol. 58, and also in his Experimental Inquiries, 11. London, 1774, pp. 64 — 

 7 1 ; in our century the existence of this system was for the rafist pai-t denied by 

 Magendie, according to whom lymphatics exist in the neck only ; he was, however, 



22—2 



