164 SKELETON OF THE PIG 



verse process is lumbar in character, plate-like, and about an inch (2 cm.) long. 

 Small accessory processes occur in the posterior part of the region. The first 

 spinous process is broad, very high, and inclined a little forward. The others di- 

 minish very gradually in leng-th to the tenth, beyond which they are about equal. 

 The second to the ninth are inclined backward, the tenth is vertical (anticlinal), and 

 the rest incUne forward. The width decreases decidedly from the fourth to the 

 tenth, beyond which there is a gradual increase. The summits are slightly enlarged 

 and lie almost in a straight line. 



The lumbar vertebrae are six or seven in number. The bodies are longer than 

 in the thoracic region and bear a ventral crest. They become wider and flatter 

 in the posterior part of the series. The arches are deeply notched, and are separated 

 by an increasing space dorsally. The mammillary processes project outward and 

 backward. The transverse processes are bent do^vI^ward and incline a little for- 

 ward. Their length increases to the fifth and is much diminished in the last. They 

 form no articulation with each other or with the sacrum. The posterior edge of the 

 root of the process is marked by a notch in the anterior part of the series, a fora- 



FiG. 172. — Fourth Lumbar Vertebra of Pig; Anterior View. 

 1, Body; 2, transverse process; 3, anterior articular process; 4, mammillary process; 5, posterior articular process; 



6, spinous process. 



men in the posterior part. The spines are broad and incline forward, with the ex- 

 ception of the last, which is narrow and vertical. 



Lesbre states that six and seven lumbar vertebra occur with almost equal frequency. The 

 number may be reduced to five, and the number of presacral vertebra; varies from twenty-six to 

 twenty-nine. 



The sacrum consists usually of four vertebrse, which fuse later and less com- 

 pletely than in the other domesticated animals. It is less curved than in the ox. 

 The spines are little developed and commonly in part absent. The middle of the 

 dorsal surface is flattened and smooth, and presents openings into the sacral canal 

 between adjacent arches (Spatia interarcualia) . On either side are the dorsal 

 sacral foramina, and tubercles which indicate the fused articular processes. The 

 wings resemble those of the ox. The anterior articular processes are very large. 

 The pelvic surface resembles that of the ox, but is not so strongly curved, and the 

 transverse lines are very distinct. 



The coccygeal. vertebrae are specially characterized by the presence of func- 

 tional articular processes on the first four or five, beyond which these processes 

 become non-articular and smaller. The arches of the first five or six are complete. 

 The transverse processes are broad and plate-like in the anterior part of the series 



