62 ELEMENTS OF MAMMALIAN ANATOMY. 



ysis of the first five bones, and an accessory process or 

 anapophysis occurs on the caudal margin of the wall of 

 the neural arch of all except the last vertebra. The 

 transverse processes increase in length and curvature 

 caudally. The spinous processes increase in length in 

 the same order, and the neural canal likewise enlarges 

 caudally. 



The sacrum is a single bone (Fig. 27) formed by the 

 union of three sacral vertebrae. The limit of each element 

 is marked by the dorsal and ventral intervertebral fora- 

 mina which furnish passage for the dorsal and ventral 

 branches of the spinal nerves. The two tubercles on 

 either side of each of the three median spinous processes 

 are the result of the fusion of the articular processes. 

 The cephalic portion of the bone presents on its lateral 

 aspect the auricular surfaces for articulation with the 

 ilium. This expansion appears to be a modified transverse 

 process. Prominent transverse processes #lso project from 

 the caudal angles. 



The caudal vertebrae vary greatly in number. Accord- 

 ing to Mivart, there are only four in the Manx cat; and 

 according to Jayne, there may be as many as twenty-six 

 in some varieties of the common cat. The transverse 

 processes and zygapophyses become less prominent from 

 the third vertebra to the eighth or ninth, where they are 

 present only as slight ridges. The spinous process is 

 present in the first three, but dwindles to a ridge in the 

 fourth. The first six or seven elements possess a neural 

 arch which' more distally loses its roof, making the neural 

 canal a mere groove. The groove becomes fainter dis- 

 tally and finally disappears entirely. The chevron bones 

 are the paired ossicles projecting ventrad from the 

 cephalic ends of the bodies of the vertebrae, from the 

 second or third to the thirteenth vertebra. In the sixth, 



