THE SKIN AND SKELETON. 143 
back a process to meet one from the squamosal, forming 
the zygomatic arch. 7. The nasal, or roof of the nose. 
8. The mawilla; that part of the upper jaw in which the 
canines, premolars, and molars are lodged. 9. The pre- 
maxilla, in which the upper incisors are situated. 10. 
The palatine, which, with the maxillary bones, forms the 
roof of the mouth. There are two appendages to the 
skull: the mandzble, or lower jaw, whose condyles, or 
rounded extremities, fit into a cavity (the glenozd) in the 
temporal bone; and the Ayozd, situated at the root of the 
tongue. 
The cervical vertebra, or bones of the neck, are peculiar 
in having an orifice on each side of the centrum for the 
passage of an artery. The first, called atlas, because it 
supports the head, has no centrum, and turns on the sec- 
ond, called axis, around a blunt process, called the odon- 
tod. The centra are usually wider than deep, and the 
neural spines very short, except in the last one. The num- 
ber of cervical vertebrae ranges from 1 in the Frog to 25 
in the Swan. 
The dorsal vertebre are such as bear ribs, which, unit- 
ing with the breast-bone, or sternum, form a bony arch 
over the heart and lungs, called the thorax. The sternum 
may be wanting, as in Fishes and Snakes, or greatly de- 
veloped, as in Birds. When present, the first vertebra 
whose ribs are connected with it is the first dorsal. The 
neural spines of the dorsal series are generally long, point- 
ing backward. 
The lumbar vertebre are the massive vertebra lying in 
the loins between the dorsals and the hip-bones. 
The sacral vertebre lie between the hip-bones, and are 
generally consolidated into one complex bone, called sa- 
crum. 
The caudal vertebre are placed behind the sacrum, 
and form the tail. They diminish in size, losing proc- 
