220 THE ANATOMY OF YERTEBRATED ANIMALS. 



the port to dura, on the upper part of the posterior face of the 

 quadrate bone, represents the stylohyal, or proximal end of 

 the hyoidean arch. 



The pectoral arch has no clavicle, and the coracoid has no 

 distinct epicoracoidal element, nor any fontanelle. The carpus 

 consists proximally of two elongated and somewhat hour-glass- 

 shaped bones, articulated respectively with the radius and the 

 ulna. The radial is the larger, and is partially articulated 

 with the ulna. Behind these, and directed transversely, lies 

 another curved ossification, the upper concave face of which 

 articulates with the ulna. It is united with the latter bone 

 on the one hand, and with the fifth metacarpal, on the other, 

 by strong ligaments, and represents a pisiform bone. Distally, 

 there lies on the ulnar side the so-called lenticular bone, an 

 oval ossicle interposed between the ulnar proximal carpal and 

 the second, third, fourth, and fifth metacarpals, the last three 

 of which it supports altogether. On the radial side, a disk 

 of cartilage, which never becomes completely ossified, is con- 

 nected by ligament with the lenticulare, and is interposed 

 between the radial proximal bone and the head of the meta- 

 carpal of the pollex. From the ulnar side of the head of this 

 bone a cartilaginous ligamentous band proceeds, over the head 

 of the second metacarpal, to the radial side of the lentlculare. 



The three radial digits are much stronger than the two 

 ulnar, and the numbers of the phalanges are 2, 3, 4, 4, 3, 

 countino' from the radial to the ulnar side. 



The pelvis (Fig. 78, C) possesses large ilia, which are firmly 

 united with the expanded ends of the strong ribs of the sacrum. 

 Tiie ischium unites with its fellow in a median ventral symphysis, 

 and, with the ilium, forms almost the whole of the acetabulum. 



The pubes take hardly any share in the formation of the 

 latter cavity in the adult. Their axes are directed forward 

 and inward, and they coalesce in the middle line ; but as the 

 inner, or median, moiety of each jDubis remains cartilaginous, 

 or imperfectly ossified, the bones, in imperfectly prepared 

 skeletons, appear as if they formed no symphysis. 



Tlie tarsus presents, proximally, an astragalo-navicular 

 bone and a calcaneum, which are less closely united than in 

 the Lizards. The latter bone has a large calcaneal process on 

 Its posterior face, the Crocodile being the only Sauropsid verte- 

 brate in which such a process is developed (Fig. 78, C Ca,). 



Two rounded distal tarsal bones, of which the fibular is 

 much the larorer, lie between the calcaneum and the third, 

 fourth, and rudimentary fifth, metatarsals. A thin plate of 



