362 William Mackenzie : 



Carnivorous Marsupials 



(Dasyurus viverrinus and Sarcophilus satantcus). 



In both the native cat and the Tasmanian Devil we see a 

 marked disproportion between the Tibia and Fibula. These 

 animals represent, wath their long Pes and close approximation 

 of Tibia and Fibula below, an approach to the Kangaroo type. 

 The head articulates with the Tibia and the Sesamoid bone. 

 Below the amount of surface entering into the formation of the 

 ankle-joint is insignificant and chiefl}' through the interven- 

 tion of the Fibro-cartilage present. The bones are well sepa- 

 rated throughout the shafts, but approach below and are firmly 

 bound together. These features are more marked in the Cat 

 (pasyurus) than in the Tasmanian Devil. 



Echidna {Tachyglossus aciileafus). 



Here we have the presence of a Hallux, though not nearly 

 so distinct as in Koala. The shaft of the Tibia is larger than 

 the Fibula, although the disproportion is not very marked. At 

 the upper end we get the prolongation into a broad, flattened 

 process resemlDling an olecranon, and articulating with both the 

 Femur and Tibia. The lower end is well developed and par- 

 takes almost as freely in the formation of the ankle-joint as the 

 Tibia. 



Lace M on I top {Varauus varins). 



In this Australian reptile, where a great mobility of the foot 

 is permissible, we have a much larger Fibula than Tibia, not 

 only as regards the shaft but also at the upper and lower ends. 

 The principal articulating surface both below with the Tarsus 

 and above with the Femur is supplied by the Fibula. 



Armadillo. 



Both bones are counnonly ankylosed together at each ex- 

 tremity but the shafts curve away from each other, leaving a 

 wide interosseous space. 



