URINARY SYSTEM OF BIRDS. 



229 



109 



Cloaca of the Ostrich. 



ducts, in the same segment of the cloaca, which is therefore termed 

 the urogenital cavity, fig. 109, e. 



The space intervening between the urogenital cavity and the 

 valvular termination of the rectum, ib. c, forms a cavity more or 

 less developed in different Birds, 

 but always distinct in the smooth- 

 ness of its lining membrane from 

 the rectum, which has a more 

 vascular and villous internal tu- 

 nic. The Birds in which this 

 rudimental urinary bladder pre- 

 sents the largest capacity are the 

 Owls, many of the Aquatic Birds, 

 as the Pelican, Willock, Grebe, 

 Swan, &c. ; some of the Wading 

 Order, as the Bittern and Bus- 

 tard, but more especially the Os- 

 trich, among the Cursores, in 

 which the urinary receptacle is 

 represented as laid open at d, fig. 

 109. 



§ 161. Adrenals of Birds. — The adrenals, d, d, figs. 117, 127, are 

 small bodies, usually of a bright yelloAv colour, situated on the 

 mesial or inner side of the superior extremities of the kidneys ; 

 closely attached to the coats of the contiguous large veins and in 

 contact with the testes in the male ; and the left one adhering to 

 the ovary in the female. They vary in shape, being sometimes of 

 a round, flattened, oval, or irregularly triangular figure. They are 

 proportionally smaller than in Mammals, being in the Goose each 

 about the size of a pea. They are sometimes confluent. 



They present, like the kidneys, a homogeneous texture through- 

 out, and do not exhibit^ the alternate strata of different-coloured 

 substances as in Mammalia. In the Gigantic Crane we found the 

 texture of the suprarenal glands to be coarsely fibrous ; in the 

 Hornbill they were granular, similar to the kidney ; in the Pelican 

 they were of a granular but more pulpy texture. 



There is no cavity in the suprarenal glands. The veins which 

 return the blood from them are of proportionally large size, as in 

 all the parenchymatous bodies without excretory ducts. The 

 suprarenal glands have been found to present a slight enlargement 

 corresponding with the increased developement of the sexual organs. 

 Their relative size and position to the testes in the male embryo 

 are shown at/, fig. 108. 



