13 I R D. 



175 



of the sternum is nearly the same ; but that as the 

 gallinule is a much more aquatic bird than I lie agami, 

 its sternum possesses two very elongated lateral pro- 

 cesses, while that of the agami is entire. The ribs 

 are also more numerous iu the agami, and occupy 

 a greater portion of the length of the sternum, and 

 though the scapular is not so long, it is broader, has 

 a slight approximation in form to that of the penguin, 

 and is strongly articulated to the head of the coracoid, 

 while that bone, though well set as to the resisting of 

 cross strains, is rather loose in its articulation with 

 the sternum as seen laterally. The furcal bone is 

 much more slender than in the gallinule, and it has a 

 process at the junction of its branches directed toward 

 the keel of the sternum as in the gallinidae, whereas 

 that of the gallinule has only a small tubercle on the 

 upper side at that point. The whole line of the furcal 

 bone of the gallinule, when viewed laterally, presents 

 an arch, though a flattened one, to the front ; while 

 that of the agami, though slightly convex near the 

 articulation with the other bones at the shoulder, is 

 concave to the front in the part next the sternum. 

 Throughout its whole length, this bone is remarkably 

 slender and foeble as compared with the sternum, 

 the coracoids, and the scapulars ; and on this account 

 the agami may perhaps be regarded as the feeblest 

 winged of bird's which have the clavicles united and 

 can use the wings in flight. The great elongation 

 backwards of the sternum makes a very marked dif- 

 ference between this bird and the ostriches, in which 

 this bone, instead of being long, narrow, and but little 

 curved, as it is in this case, is short, broad, and very 

 convex on the under or external surface. The 

 habit of the bird corresponds ; for while the ostrich 

 family, in whatever part of the world they reside, are 

 found on dry if not parched and naked pastures, the 

 agami is found native in richer places, near the 

 perennial waters, but on the verge of the tall aquatic 

 herbage rather than in the middle of it. The agami 

 is thus intermediate in its locality between the ostrich 

 and the gallinulcs, and other macrodacty lie birds; and 

 itisnotalittle remarkable that its sternal bone partakes 

 of the undivided character of that of the one race, and 

 the elongated one of the other. 



Sterna of the crane family. The cranes and the 

 herons are not only found in places bearing consider- 

 able resemblance to each other, but some of the species 

 are externally so much alike that they have been 

 very generally considered as forming one tribe and 

 sometimes only one genus. 



The grand distinction between the cranes and the 

 herons, whether we consider them as distinct groups 

 or merely as genera (and the distinction is perhaps 

 broad enough to amount to the former), is that the 

 cranes have much more of a landward character than 

 the herons, and they are also much more discursive 

 and migratory, though from their habit of fishing or 

 otherwise feeding in the shallows of the waters, herons 

 are also necessarily migrant in those parts of the 

 world which are alternately flooded by water and 

 parched by drought. 



The sternum of the cranes is of moderate length, 

 rather narrow, very little hollowed on the upper sur- 

 face, and of nearly equal breadth throughout its whole 

 extent. The sternal crest is large in proportion to 

 the whole extent of the bone ; arched on the under 

 side for the ureatcr part of its length, but slightly 

 concave toward the posterior extremity; and in some 

 of the species it contains a large cavity in which a 



flexure of the windpipe is lodged, as is also the ease 

 in some of those long-necked swimming birds which 

 seek their food with the head immersed in water. 

 The angle of the crest advances considerably in front, 

 is rounded, and, in the true cranes, and some other 

 species, united to the central part of the clavicle. 

 Seen in profile, the sides of the sternum appear con- 

 cave ; and in the rear it is divided by two triangular 

 notches, which form the posterior angles into two 

 processes which extend a little, but not much, beyond 

 the central part. The coracoids are short, strong, and 

 much enlarged on their posterior sides. The clavicle 

 is open, though but slightly arched in the plane of the 

 opening. It is much enlarged toward the shoulder- 

 joints, and much more arched toward the front than 

 laterally. The blade bones are long, flat, and slightly 

 bent, but not so large in proportion as in the agami. 

 Tile following figures of the sternum of the white 

 stork, on a scale of half the natural size, may be con- 

 sidered as an average specimen. 



White Stork. 

 Profile of the same bone on the same scale. 



White Stork. 



On examining this sternal apparatus it will be seen 

 that though the keel is well developed, and the 

 shoulder also moderately firm for flight, yet that the 

 extent of the scapular, the arching toward the front 

 of the clavicle, and the union of that bone with the 

 angle of the sternal keel, throw a portion of the sup- 

 port upon the back and thence to the legs, which in 

 all the species are well adapted for walking. Still, 

 though these birds cannot be considered as possessing 

 either very swifc or very ready wings, they have all 

 considerable ower of continuance on their flight. 

 They are also light birds in proportion to the extent 

 of their wings, and therefore they fly high on their 

 long flights ; and, as is the case with the trnegrallida; 

 or wading birds, they fly with the feet backwards, and 



