us //// /; -w - 



particularly in walking birds, and eom|>osed, as in the mammalia, of an ilium, ischium. 

 and mibis." The ilium is consolidate! wit!) tli. l.i-j .1 r-.l tin- lumbar, an<l tin 

 \ertehriB ; it is exeavati tl on its internal face. Tin- itrlilnm partly incloses tin- side of 

 the pelvic cavity; between its internal border and tin external Inrder of tin- ilium i- an 

 orifice which replaces the great ischialie notch. Its inferior Inirder is united to the /"</>/*. 

 The latter is thin and elongated, and follows the direction of the inferior border of the 

 idchium, with it circumscribing an oral <>i nin<j more or less spacious. Its inferior 

 i \tr. mity extends beyond the iachiumto curve inwards towards that of the opposite fide, 

 but without uniting with it. We do not, therefore, find the pelvic Kvmphysis in bird*. 

 and the jN'lvis is widely OJHJII below, a circumstance which favours the |wssage of the 

 egg through the cavity a'nl out of the cloaca. The cdd/Io'il <-nritij is jM-rfor.iti-d by an 

 opening at the bottom which traverses the bone. 



Thigh bone. f he femur is articulated inferiority with the pat llu, tibia, and fibula. In 

 all walking birds, like the. gallinacte, it is long and strong, as well as the rays below it. 



Leg bones. The patella is wide and thin. The tibia terminates, below, by two BOft- 

 dyles separated by a groove which becomes articular behind. The fibula articulates 

 by its head with the external condyle of the femur, and is consolidated with the tibia : 

 it never descends to the inferior extremity of that bone. 



Tarsal bones. The tarsus appears to be altogether absent in birds. Nevertheless 

 we may venture to consider, as a vestige of the bones of this region, a small bony nnd'-m 

 buried in a fibro cartilaginous mass which glides on the posterior pulley of the tibia. 

 This nucleus represents the calcaneus of mammals. 



Metatarsal bone. A single metatarsal bone is found in birds, articulating superiorly 

 with the inferior extremity of the tibia, and terminating inferiorly by three pulleys 

 which support the three principal digits. This bone shows in the f'oirf, near its inferior 

 third, a conical process turned backwards, which serves as a base for tho spur. Behind 

 its superior extremity, it exhibits another which may be considered as a consolidated 

 metatarsal bone. 



Bones of the digital retn'on. All the domesticated birds have four digits on the inferior 

 members: three principal, directed forwards, and one rudimentary, carried backwards. 

 The first, designated ns internal, median, ami external, articulate with the inf-rior 

 pulleys of the metatarsal bones. The internal is formed by three phalanges, the 

 has four, and the third five. These phalanges are formed something like those of the 

 earnivora: the last is pointed, conical, and enveloped in a horny sheath. The fourth 

 digit, or thumb, is composed of three pieces: one of these, the fir.-t, is generally con- 

 sidered as a rudimentary metatarsal bone. It is attached by fibvo-cartilaginous tissue 

 to the inner and posterior aspect of the inferior extremity of the principal metatarsal 

 bone. 



CHAPTER IV. 



THEORY OF THE VERTEBRAL CONSTITUTION OF TIIK SKELETON. 



IN the series of vertebratod animals, the bony pieces of the trunk 

 the name of vertebra) are those which offer the highest degree of fixity, and 

 to which the existence or the arrangement of the others appears to be subor- 

 dinate. This feature in organisation, recognised by E. Geoffroy Saint- 

 Hilaire and Professor Owen, has caused these men of science to assert that 

 the type of construction of vertebratod animals is the vertebra. 



After E. Geoffroy Saint-Hilairo and Professor Owen, several German 

 English, and French anatomists have studied the vertebral composition of 

 the skeleton; and among the works published in Franco on this subject must 

 be specially noticed those of M. Lavoctit ! In principle, all the writers 

 have arrived at the same conclusions, and only differ in some few details. 



It is certain that the base of the vertebral column is formed by a series 

 of bony segments. Each of these segments is called an ostcodcsm, and each 

 osteodesm represents the body or centrum of a vertebra. 



(' The distinguished anatomist and Director of the Imperial Veterinary School of 

 Toulouae.) 



