1 SKELETON 9 
phalanges (joints); the second the Index, representing man’s first 
finger, with two or three joints; the third a weak digit with only 
one phalanx, except in Archaeopteryx, where there are four. The 
Casuarii and Apteryges possess an index only, which in the Sphenisee 
fuses with the pollex. The basal joint of this is the normal 
place of attachment of the “bastard wing” (alula spuria). 
Archaeopteryx had claws on all its fingers, but in recent Birds 
they occur on the first two only, being functionless in the adult. 
Wing-spurs arise from the carpal and metacarpal bones, 
6. The Pelvic Arch consists of the Ilium, Ischium, and Os 
pubis, these three paired bones meeting from each side at the cup 
(acetabulum) that receives the head of the femur, and coalescing 
early in hfe; while the dncisura ischiadica or notch between the 
Fig. 4.—Pelvis of Apteryz australis. Lateral view. a, Acetabulum ; 7, ilium ; 7s, ischium ; 
Pp, pectineal process of pubis ; p', pubis. (From Wiedersheim, after Marsh.) 
ischium and the ilium becomes an inclosed space (foramen) in 
all Birds except the Ratitae and Crypturi. 
7. The Posterior Limbs, or Legs, are composed of the Femur 
or thigh, the Tibia and Fibula, making the shank or “drum- 
stick,’ and the bones of the Foot. The thigh, however, being 
hidden by the plumage, the shank of a Bird might easily be 
taken for the thigh, and the metatarsus (the cannon-bone of some) 
for the shank. The tibia and fibula commonly unite to some 
extent, and the former, as it now exists in adult Birds, is strictly 
a “ tibio-tarsus,” since with it is fused the proximal portion of the 
originally existing tarsal elements. Similarly the distal tarsal 
