EXCRETING ORGANS. 633 







trated and shorter form, and are less distinctly lobulated 

 than in most inferior vertebrata ; their surface presents a 

 convoluted appearance, as in crocodiles, from the tortuous 

 forms of their component lobules. The tubuli uriniferi are 

 more tortuous in their course in the chelonian than in the 

 crocodilian reptiles, but arise in a similar manner from the 

 ramified ureters. Their urinary bladder is of greater size 

 than in any other vertebrata, which accords with their suc- 

 culent vegetable nutriment and their limited cutaneous per- 

 spiration ; generally it is partially divided into two, and some- 

 times into three lobes at its upper part. Like the respira- 

 tory allantois of the foetus of higher classes, it is a great folli- 

 cular or hernial development from the cloacal part of the 

 intestine, and although, as usual in oviparous vertebrata, 

 the ureters do not terminate directly in it, but behind its 

 cloacal orifice, uric acid is found in its viscid contents, as in 

 the similar large urinary bladder of the batrachian animals. 



The kidneys of birds are still constantly and deeply 

 divided, especially at their posterior ends, into numerous 

 lobes of considerable size, covered on their ventral surface 

 only with peritoneum, and lodged immediately behind the 

 lungs in the deep fossae along the sides of the sacrum. They 

 are elongated in form, diminishing in size from before back- 

 wards, constricted in their middle, symmetrical, placed be- 

 tween the same transverse plains of the body, deeply sulcatedon 

 their dorsal surface by the transverse processes of the sacrum. 

 The component lobes are most numerous and distinct in the 

 ostrich, and least apparent in some of the palmipeds, as the 

 pelican. The largest anterior lobe of each kidney receives 

 a distinct renal artery from the trunk of the aorta, and the 

 smaller succeeding lobes receive branches from the femoral 

 arteries, or from the sacra media prolonged from the aorta. 

 The surface of the lobes, when closely examined, presents a 

 convoluted appearance, as in many reptiles, from the tor- 

 tuous distribution of the small lobules, formed by the shut 

 ends of the ultimate tubuli uriniferi, as shown by Ferrein, 

 and tufts of these tubuli end in small calyces, as in mammalia. 

 The simple narrow ureters collecting the secretion from the 

 renal lobes, and extending along the ventral and inner surface 

 of the kidneys, without forming a pelvis, open directly into 

 the dorsal and lateral part of the cloaca, by two prominent 



