LIMBS OF VERTEBRATES. 375 
bodies of each vertebra of a lizard, bird or mammal being 
solid bone. Figs. 370 and 371 represent the relations of the 
notochord in an adult lamprey and a young fish. 
The vertebra of a bony fish 
or higher vertebrate consists 
of a body, with a dorsal or 
neural spine; a pair of oblique 
processes (zygapophyses) arching 
over and enclosing the spinal | { 
cord; and transverse processes, 
bending downwards, to which 
the rids are articulated ; certain 
of the thoracic ribs uniting 
with the sternum or breast-bone_ ,, 7S 
(Figs. 372 and 373). wt its body (HD), brenst bong 
Vertebras like those of fishes, Sot Gonene tamer oLaanaeies 
which are hollow or concave at Press 
each end, are said to be amphicelous ; those hollow in front 
and convex behind procelows, as in most toads and frogs 
and crocodiles, and most existing 
lizards, and those convex in front 
and concave behind opisthocelous, 
as in the garpike, some Amphib- 
ians (the salamanders and cer- 
tain toads, Pipa and Bombinator). 
Big, Sil mncnante, ‘vertehia: st Vertebrates never have more 
buzzard (Buteo vulgaris). c, centrum than two pairs of limbs, an an- 
er body ;-8, superior spinous pro- 4 is ‘ 
cess; ¢r, transverse process; #0, terior and hinder pair ; the pecto-. 
rib; @, taberculum of the rib : 3, ca- * 
piisinm of fie Hb—Ather fecen- ral pair of fins of fishes represent 
baur. the fore limbs of Amphibians and 
higher Vertebrates, and the arms of man; the two ventral 
fins represent the hind legs of higher Vertebrates, and the 
legs of man. ach pair of limbs is connected by ligaments 
and muscles to a girdle or set of bones, called respectively 
the shoulder girdle and pelvic girdle, each girdle being con- 
inected by muscles to the vertebral column. ‘The shoulder 
girdle consists of a clavicle (or collar-bone), scapula (or 
shoulder-blade), and coracotd bone, usually a process of the 
scapula. These bones differ greatly in the different classes, 
Lhe 2 
' 
Ww 
