6 THE SKELETON OF THE CAT. 



of the centrum immediately preceding is not marked by any 

 part of it. In the eleventh thoracic vertebra each costal facet 

 is usually still confluent with the smooth cranial end of the 

 centrum. In the twelfth vertebra the facets are separated by 

 smooth ridges from the cranial end of the vertebra, while in 

 the thirteenth vertebra they are separated by rough ridges. 



The spinous processes (cz) of the first four are of about the 

 same length. They then decrease in length to the twelfth, 

 while the twelfth and thirteenth are slightly longer than the 

 eleventh. The first ten slope more or less caudad, while the 

 spinous process of the tenth vertebra is nearly vertical and 

 those of the eleventh, twelfth, and thirteenth point craniad. 



Each of the transverse processes of the seventh thoracic 

 vertebra shows a tendency to divide into three tubercles; one 

 of these is directed craniad, the mammillary process (or meta- 

 pophysis), one caudad, the accessory process (or anapophysis), 

 while the third (transverse process proper) looks ventrad and 

 bears the transverse costal facet. This division becomes 

 more prominent in the succeeding vertebrai, being most 

 marked in the ninth and tenth. In the eleventh, twelfth, and 

 thirteenth vertebrae the mammillary {g) and accessory (/) 

 processes are very pronounced, while the transverse costal 

 facet and that part of the transverse process which bears it have 

 disappeared. The ribs of the eleventh, twelfth, and thirteenth 

 vertebrae are thus attached to their respective centra by their 

 heads alone. 



The cranial articular processes (J?) are prominent on the 

 first two thoracic vertebrae; back of these they are very small 

 as far as the eleventh, so that the articular facets seem to be 

 borne merely upon the dorsal surface of the cranial edge of the 

 laminae. In the eleventh, twelfth, and thirteenth the cranial 

 articular processes are large, bearing the articular facets on 

 their medial surfaces, while the mammillary processes appear 

 as tubercles on the lateral surfaces of the articular processes. 

 The caudal articular processes (//) are prominent in the first 

 thoracic, then^smaller until the tenth is reached; in the tenth, 

 eleventh, twelfth, and thirteenth they are large and their facets 

 are borne laterally, so as to face the corresponding cranial 



