518 



ANATOMY OE VERTEBRATES. 



on the upper part of the base of the diapophysls. The homotypal 

 ridge may be recognised on the first sacral vertebra. There are 

 rudiments of hypapophyses on the middle caudal vertebrae. 

 Seven pairs of ribs articulate with the sternum, which consists of 

 seven bones and an ensiform cartilage. The transverse process 

 of the atlas is perforated lengthwise and vertically by the verte- 

 bral artery ; which afterwards pierces the neural arch : the neural 

 spine is represented by a small tubercle, and there is a hypapo- 



344 



elvmrraMS'.sj 



Mandrill. (Papis Maimon.) 



physial ridge. The centrum of the axis is much produced back- 

 ward, underlapping that of the third vertebra : this character is 

 gradually lost in the succeeding vertebrte : the transverse process 

 of the axis ends in two tubercles. The lower (pleurapophysial) 

 division of the process is compressed in the third cervical, and be- 

 comes developed into a plate, progressively increasing, and dis- 

 proportionately so in the sixth cervical: it is absent in the 

 seventh cervical, the transverse process of which is, however, 

 still perforated by the vertebral artery. The neural spines are 



