522 



ANATOMY OF VERTEBRATES. 



345 



vertebral artery is thus not quite circumscribed by bone : tlie 

 artery afterwards j^ierces the neural arch on the left side, and 

 deeply grooves it on the right side. The two portions of the 

 transverse process of the axis have coalesced, and form a thick 

 tubercle externally, surrounding the vertebral artery : this tubercle 



increases in breadth in the third, and 

 in length in the fourth ; in the fifth it 

 sends a distinct tubercle from its lower 

 part, and the answerable part forms an 

 antroverted, obtuse, broad process in 

 the sixth. The pleurapophysial ele- 

 ment is wanting in the seventh, in 

 which the diapophysis is deeply grooved 

 below for the vertebral artery. The 

 spines of the 4 — 7 cervicals are long 

 and simple. A metapophysis may be 

 distino^uished in the eleventh and 

 twelfth dorsals, which becomes distinct 

 from the diapophysis in the thirteenth, 

 and projects from the outside of the 

 prozygapophysis in all the lumbar ver- 

 tebrae. The diapophyses are longest 

 in the first and second lumbars, are 

 shortest in the third, and are augmen- 

 ted in the fourth by the developement 

 of a thick anapophysis at their back 

 part, which here articulates with the 

 first sacral vertebra. In old males the 

 fourth lumbar becomes the first sacral 

 by a more complete coalescence. Seven 

 pairs of ribs directly join the sternum, 

 which consists of five flat bones and 

 an ensiform part : the fourth and fifth 

 bones have coalesced : the manu- 

 brium, as in the Orangs, is the broad- 

 est, and receives the first pair and part 

 of the second pair of ribs. These are 

 shorter, and their neck relatively 

 longer than in the Orang, and they 

 are more curved. The thirteenth rib 

 retains a distinct articular tubercle and neck. 



In the Gorilla ( Troglodytes Gorilla, fig. 346), the dorso- 

 lumbar vertebra?, as in the Chimpanzee, are 17 in number, the 



Cliinipaiizec (Troglodytes Niger), cur. 



