OR OSSEOUS SYSTEM. 79 



ness of the anchylosed nasal bone ; the palatine bones are 

 more fixed than in serpents, and are destitute of teeth, and 

 the two pterygoid bones (v,) extend, as in serpents, back- 

 wards and outwards to the tympanic (r.) The lower jaw is 

 divided at the symphysis, and consists on each side of six 

 pieces, of which the anterior or dental portion is the largest, 

 and the prehensile teeth are here as loosely attached by 

 their expanded base to the alveolar flat surface of the jaw, 

 as in serpents, protected at their bases by an outer, and 

 sometimes an interior ridge of the dental bone, but not 

 lodged in separate alveoli. The osseous bases of these 

 teeth in the lizards often anchylose to the surface of the 

 jaws, as in fishes, and the new teeth generally rise up on 

 the inner side of the base of the old or of the lost, and not 

 in the interior of their cavity, as they do in the croco- 

 diles. 



The ribs of lizards are for the most part rounded and 

 slender, and without the tubercle so much developed in 

 quadrupeds and birds. The scapula is thin, broad, and 

 curved ; the coracoid also terminates in front by a very 

 broad curved margin by which it unites to the large ento- 

 sternal piece. The acromion is a distinct bone of very 

 variable size and form, and the clavicles are anchylosed and 

 extended in form of a cross along the fore part of the ster- 

 num. The sternal elements are thin, soft, and extended 

 transversely, and have chiefly the ento-sternal enlarged 

 and strong, as in birds. The humerus, also as in birds, is 

 much expanded at its upper and lower extremities, the ulna 

 is much stronger than the radius, and distant from it, espe- 

 cially at the carpus. There are nine bones in the carpus, 

 as in tortoises. The three pelvic bones contribute to the 

 formation of the cotyloid cavity for the head of the femur. 

 The expanded edges of the ossa pubis, and ossa ischii meet 

 and form a lengthened symphysis on the median line in 

 front, and the spine of the iliac bones is extended, not for- 

 wards, as in higher classes, but backwards along each side 

 of the sacrum towards the coccygeal vertebrse. The head 

 of the femur is compressed, and bent forward, and the great 

 trochanter is also compressed and turned towards the tibia. 

 The patella is always small, the tibia short, strong, thick at 

 its ends, and much curved at its fibular margin. The fibula 



