456 Dr. Davy on the Temperature, fyc., of Birds. [1865. 



they are, the less translucent they are, and consequently the lighter is the 

 colour, being less affected thereby by that of their contents. The long 

 bones of the common guillemot, and also of the corn-crake, the parietes 

 of which, especially of the wing-bones, are more than ordinarily thick, may 

 be mentioned as illustrative examples. 



In a preceding part of this paper I have referred to the size of some of 

 the more important organs of birds. lu many instances I have ascertained 

 their weights. As examples, those of five different species are selected, and 

 I give them without comment. 



1. Tawny owl. Weight 5776 grs. April 7.' grs. 



Brains, its membranes detached 139 



Eye freed from muscle and fat 91 



Lens (-58 inch diameter) 1 9'6 



Skin freed from most of its fat 250 



Membranous stomach 115 



Liver without gall-bladder 1 54'7 



Spleen 1 4'6 



Pancreas 9'5 



Kidneys 577 



One lung, it contained a little coagulated blood 13'2 



Heart freed from fat 39 



Testes (no spermatozoa could be detected in them) .... 2*5 



Great pectoral muscles 634 



Other muscles of chest, those attached to furcula and sca- 

 pular arch, exterior of costal 198 



Muscles of humeri 188 



Muscles of ulnae and radii 156 



Muscles of femora 272 



Muscles of tibiae 346 



2. Rook. Weight 6556 grs. April 19. 



Brain freed from its membranes 1 18*6 



Eye formed from muscle and fat * 41 



Skin, exclusive of that of tarsi and phalanges, or very 



little fat adhering 344 



Gizzard 208 



Liver, gall-bladder detached 167 



Spleen 2-8 



Pancreas 23'2 



Kidneys 72'6 



* Of another male rook, shot April 29, and examined whilst still warm, the eye weighed 

 37-6 grs., the lens 1-2 gr. ; it was very soft ; evaporated to dryness it lost '75 gr., or 62-5 

 per cent, of water. The lens of the rook, of that of which the weight of the organs is 

 given above, was almost as liquid as the vitreous humour. 



