48o KIDDAW— KIDNEYS 



verioides in Florida.^ Of other Kestrels it remains to say that T. 

 jnoluccensis is widely spread throughout the islands of the ]\Ialay 

 archipelago, Avhile T. cenchroides seems to inhabit the whole of 

 Australia, and has occurred in Tasmania (Proc. Roy. Soc. Tasmania, 

 1875, pp. 7, 8). No Kestrel is found in New Zealand, but an 

 approach to the form is made by the very peculiar Harpe iiovse- 

 zelandise (of which a second race or species has been described, H. 

 brunnea or H. ferox) the "Sparrow-Hawk," '• Qu AIL -Hawk," and 

 "Bush-Hawk" of the colonists — a bird of much higher courage 

 than any Kestrel, and perhaps exhibiting the more generalized and 

 ancestral type from which both Kestrels and Falcons may have 

 descended. 



KIDDAW, one of the many local names of the GUILLEMOT. 



KIDNEYS, renes, the organs of the Excretory System for the 

 discharge as urine of the nitrogenous waste-matter of the blood. 

 In Birds they are comparatively large, weighing about one- 

 hundredth part of the whole body, and extend from the posterior 

 margin of the lungs to nearly the end of the pelvis, filling the 

 ca^dties between the iliac bones and the sacral vertebrse, the trans- 

 verse processes of which produce deep impressions upon the dorsal 

 surface of the Kidneys, and di\dde them into a number of irregular 

 lobes ; but their ventral surface is almost smooth. Near their 

 anterior end, and close to the vertebral column, lie the genital 

 glands (ovaries or testes), the ducts of which (oviduct or vas deferens 

 as the case may be), run, together with the lu-eter, upon the 

 ventral surface of the Kidneys. Resting against these glands, there 

 is on each side a reddish or yellowish -brown body of irregular 

 shape, the supra-renal or adrenal capsule, an organ of still problematic 

 significance. In most Birds each Kidney is more or less divided 

 into three lobes, of which the anterior is generally the largest, and 

 the middle one the smallest. Sometimes the two Kidneys partly 

 coalesce across the vertebral column, so that the unpaired dorsal 

 aorta and the inferior vena cava are enclosed in their substance ; 

 but their shape, size and the number of their principal lobes 

 depend much on the configuration of the sacrum and pelvis, and 

 are scarcely of practical taxonomic value. The Kidneys are shut 

 ofi" from the body-cavity by a peritoneal lamella, and their minute 

 structure as well as their vascular system is very complicated. 

 Each possesses a transparent sheath of connective tissue, on the 

 removal of which the dark brown substance of the organ is seen to 

 consist of an enormous number of convoluted and tightly-packed 

 lobules, and each of these lobules is pervaded by renal arteries and 

 veins with their capillaries, and contains the uriniferous tubules that 



1 The absence of any Kestrel from Jamaica is a most curious fact, considering 

 the abundance of the form in other parts of the West Indies. 



