PHYLUM CHORDATA 



529 



nearly equally developed. In the hind-foot the fourth toe 

 is much longer and stouter than the others, while the second 

 and third are small and slender, and united together by a 

 web of skin, and the first is vestigial or absent. The marsu- 

 pium has its opening directly backwards. 



The wombats (Phascolomyidce) are large, heavy, thick- 

 bodied, burrowing animals, with short flattened heads, short 

 thick limbs, provided with strong claws on all the digits 

 except the hallux, and with the second, third, and fourth of 



Fig. 317. — Dasyure (Dasyurus viverrinus). (After Vogt and Specht.) 



the hind-foot partly connected together by skin. The tail 

 is very short. The kangaroos and their allies (Macropodida) 

 (Fig. 318) are adapted, as regards their limbs, for swift 

 terrestrial locomotion. They have a* relatively small head 

 and neck, the fore-limbs small, and each provided with five 

 digits; the hind-legs long and powerful; rapid progression 

 is effected by great springing leaps, with the body inclined 

 forwards and the fore-limbs clear of the ground. The 

 foot is narrow and provided with four toes, the hallux 

 being absent ; the two inner (second and third) small and 



