380 



ANATOINIY OF VERTEBRATES. 



In the prolific Giiinea-Pig, the pelvis, fig. 245, is long and 

 laterally compressed, the passage being mnch narrower than the 

 diameter of the head of the mature foetus. Prior to parturi- 

 tion the symphysial ligaments become soft and extensile, and the 

 innominata, gliding on the sacro-iliac joints, diverge at the sym- 

 physis to the extent shown in fig. 246 during parturition. After 

 this process the symphysis quickly returns to its former or normal 



2-15 246 



Pelvis of the Guinea-Pig seventy-two hours 

 after parturition. 



Pelvis of the Guiuea-Pig at the time of 

 parturition. 



state, and in a few days presents only a little thickness and 

 mobility. The young of the Guinea-Pig are far advanced at 

 birth, some of the deciduous teeth are shed in utero, and they 

 run about and begin to eat soon after they see the light. 



In the Water-Hog, or Capybara, there is no complete clavicle. 

 The acromion is long and slender, and bifid at its extremity, with 

 the longer division directed downward. The humerus is widely 

 perforated between the condyles, but not above the inner condyle : 

 both this bone and the ulna are solid. The scaphoides and lunare 

 are connate. The pollex is wanting in the fore feet, and both 

 the hallux and the fifth toe are wanting on the hind feet. The 

 ungual phalano^es are short, obtuse, and broad. 



