THE RIBS 165 
and diminish very gradually. Not rarely the first coccygeal vertebra unites with 
the sacrum. 
Vertebral Curves.—The cervical region is practically straight. The thoracic 
and lumbar regions form a gentle curve, concave ventrally, the highest point of 
which is at the junction of the two regions. The sacral promontory is not so pro- 
nounced as in the ox, and the sacral curve is flatter. 
Fic. 173.—Sacrum anv First CoccyGeat VERTEBRA OF Fic. 174.—Sacrum anp First CoccyGEAL VERTEBRA OF 
(Pic; Dorsat View. Pic; Ventra VIEW. 
I-IV, Arches of sacral vertebre; 1, 2, 3, dorsal sacral I-IV, Sacral vertebre (bodies); 1, 2, 3, ventral sacral 
foramina; 4, similar foramen between sacrum and first foramina; 4, similar foramen between sacrum and first 
coccygeal vertebra; A, body of first sacral vertebra; B, coccygeal vertebra; A, body of first sacral vertebra; B, 
articular process; C, wing; D, auricular surface; E, articu- articular process; C, wing; D, auricular surface; £, first 
lar processes; F, first coecygeal vertebra. coccygeal vertebra. 
Length.—The regional lengths of the vertebral column of a large Berkshire sow were as fol- 
lows: Cervical, 24 cm.; thoracic, 53.5 em.; lumbar, 31 em.; sacral, 17 em.; coccygeal, 35 em. 
Variations.—The occurrence of fifteen thoracic vertebre is quite common, and the existence 
of sixteen or even seventeen has been recorded. Reduction to thirteen is very rare. Six and 
seven lumbar vertebrz seem to occur with about equal frequency, and reduction to five is on rec- 
ord. The number of coccygeal vertebre varies from twenty to twenty-six according to the records 
of several observers. Lesbre states that he has found twenty-three most frequently. 
THE RIBS 
The ribs number fourteen or fifteen pairs, of which seven are sternal and seven 
or eight asternal usually. They are in general strongly curved in the improved 
breeds, so that there is a fairly distinct angle, except toward the end of the series. 
