BIRDS. 



BIRDS. 



1(52 



either formed of one piece distinct from the skull and articulated with 

 it, as in the parrots ; or it is connected with it by means of yielding 

 elastic bony plates, as in most other birds. These elastic plates 

 admirably protect the bill (the upper part of which may be considered 

 as an elongation of the intermaxillary bones) and the skull from the 

 shocks of the former organ when used in pecking violently against 

 hard substances. 



In a few instances the upper jaw is entirely immovable. Blumen- 

 bach gives the Rhinoceros Bird and the Cock of the Wood (Tetrao 

 Urogallm) as instances. 



Bvnet of Ike Neck and Trunk. The upper limbs, or, to speak more 

 correctly, the anterior extremities of birds are calculated for flight, 

 and entirely useless as prehensile organs, because the bird depends 

 principally upon its bill to gather its food. To give a greater freedom 

 of action to this organ, it was necessary, as the bones of the back have 

 hardly any motion (the dorsal vertebrae being often anchylosed or 

 immovably fixed by a continuation of bony secretion), that the neck 

 should be long and flexible ; and eminently flexible it is. In the 

 mammifers the number of cervical vertebrae (neck-bones) is seven ; 

 the Cameleopard (Giraffe) has no more, and the Elephant and Whale 

 have no less. Cuvier indeed gives the Sloth nine. Professor Thomas 

 Bell however has satisfactorily made out that the additional two are 

 bones of the back, not of the neck. But, in Birds, nature has made 

 up for the deficiency of motion in the back (a deficiency absolutely 

 necessary to the comfortable existence of the animal, inasmuch as the 

 back is the point of support to the wings) by the free grant of cervical 

 vertebrae, according to the want* which the peculiar habits of parti- 

 cular birds require. Thus the Raven has 12 neck-bones, the Domestic 

 Cock 13, the Ostrich 18, the Stork 19, and the Swan 23, the largest 

 number it is believed yet detected, while the smallest amounts to 10. 

 The articulation is so contrived as to produce the greatest mobility, 

 and that the contrivance is complete is proved by the ability of a bird 

 to touch every point of itg body with its bilL 



The vertebrae of the back are from 7 to 1 1 in number. There are 

 no true lumbar vertebrae, for they are consolidated into one piece with 

 the pelvis (os innominatum) which is elongated, broad, and simple ; 

 and does not unite below, as in mammifers, to form what is called the 

 symphysis pubis, but has the lateral portions, distinct from each other. 

 This is the general rule. The pelvis of the ostrich forms an exception ; 

 for it is joined below like that of most quadrupeds. In mont of the 

 quadrupeds the rump-bone (os coccygis) is prolonged into a true- 

 jointed tail. In birds it never is, but is very short, although it supports 

 the large tail-feathers (rectrices). 



Ten pairs of riba are said to form the maximum among l.inls ; these, 

 the true ribs, are joined to the breast-bone (.sternum i l.y small inter- 

 veiling bones. The false ribs (those which do not reach the breast- 

 bone) have a forward direction. There is a peculiar flat process 



Skeleton of Sparrow Hawk. 



A, Cranium or Skull. B, Cervical vertebrae. 



C, The dotted lines indicate the extent of the anchyloscd vertebra) of the back. 

 I), The caudal vertebne ; the letter is placed on the ploughshare, or rump-bone. 

 K, Ribs. F, Sternum, or breast-bone. G, Furcula, or merry-thought. 



HH Clavicular, or coracoid-bone, 1 sidesman. 



H*, Scapula, or shoulder-blade, j 

 I, llumerus, or bone of the arm. 



K, Ulna, ) Bones of the fore-arm : on the nlna is the place of insertion of 

 L, Radius, f the secondary quills. 



M, Metacarpnl bones, part of the hand which carries the primary quilis. 

 N, Phalanges of the fingers. 

 O, Ilium, 



Bones of the pelvis. 



P, Pubis, 



Q, Ischiutn, 



R, Femur, or thigh-bone. 



S Tibia and fibula, or leg-bones consolidated. 



V V, Metatarsal, or shank-bones. 



o o, Patella, or knee-pan. 

 T, T, Os calcis, or heel-bone. 

 W \V, Toes. 



Wing-bones in dctai 1 . 



C, Outline of part of furcula ; II*, outline of fart of scapula ; T, huircnii", r.r 

 bone of the arm ; K, ulna ; L, radius bones of the fore-arm ; on the u'.nn nrc 

 the marks of insertion of the secondary quills; * *, carpal bcnes, or wrist; 

 M M, metncarpnl bones ; M*, thumb ; N N N, phalanges of the flngers. 



