494 



CHORD AT A. 



body, covered not only with thick fur but with strong 

 pointed spines scattered amongst the hair. The general 

 colour is brownish and the spines are usually yellowish. 

 The facial part of the head is produced into a long tubular 

 rostrum. The eyes are small. The limbs each have five 

 toes and in- the typical species all are clawed. The tongue 

 is long and protrusible. There is a small poison-spur on 

 the hind-limb. The tail is almost absent. The animal is 

 fossorial and anteating in its habits and can burrow rapidly. 

 It is said not to make a nest but to carry its egg, which 

 has a thin horny shell, in a temporary pouch. The mam- 

 mary glands are like those of Ornithorhynchus. The skull 



Fig. 339. — Skull of Ornithorhynchus x \. 



Maxilla. *■ 

 Intermaxillary. 



Horny Pad 



Zygomatici 

 Arch. 



Foramen Magnum 



Symphysis. 



Horny Pad. 



Condyle 



A, Ventral view of skull. B, The mandibles from above. 



of Echidna^ in its modifications for ant-diet, is rather like 

 that of the true anteaters. We may note (i) the absence of 

 teeth ; (2) the great elongation of the facial region; (3) the 

 degeneration of the lower jaw or mandible. The functions 

 of teeth and lower jaw have largely been usurped by a long 

 adhesive tongue. 



Order II. — Allotheria, 



These consist of a series of small extinct mammals 

 {Flagiaulax^ Microlestes), chiefly known to us by their 

 mandibles or lower jaws and their teeth. They occur in the 



