CHARACTERS OF PROTOTHERIA. 



683 



plates. It makes long burrows in the banks, often with two openings, 

 one above, one under the water. The animal is shy, and dives swiftly 

 when alarmed. When about to sleep, it rolls itself into a ball. In the 

 recesses of the burrows the eggs are laid, two at a time. The egg 

 measures about three quarters of an inch in length, and is enclosed in a 

 "strong, flexible, white shell," through which the young animal has to 

 break its way. 



The full grown duckmole measures from eighteen to twenty inches in 

 length ; the male slightly exceeds his mate. The fur is short and soft, 

 dark brown above, lighter beneath. The jaws are flattened like the bill 

 of a duck, and covered with naked skin, which forms a soft, sensitive, 

 collar around the region where the bill joins the skull. The eyes are 

 very small ; there is no external ear flap or pinna ; the nostrils lie near 

 the end of the upper part of the bill. The tail is short and flat. 



Horny plates, two on each jaw above and below, serve as teeth in the 

 adult. True teeth, three on each jaw above and below, are calcified, but 



-v.d. 



FIG. 245. Urinogenital or- 

 gans of Male Duckmole. (After 

 OWEN.) 



BL, Bladder; u., ureter; v.d., vas 

 deferens ; r.^ rectum ; /., gland ; cL, 

 cloaca ;/., penis ; u.g.c., urine-genital 

 canal. 



FIG. 246. Urinogenital or- 

 gans of Female Duckmole. 

 (After OWEN.) 



Ov, ovary ; od, oviduct ; ut, ' ' uter- 

 ine" region; u, ureter; r, rectum; 

 uv, bladder ; ug, Urinogenital sinus ; 

 cl, cloaca. 



soon worn away and shed. The digits are clawed and connected by a 

 web which is best developed on the fore limbs. The spur borne on the 

 heel seems to be sometimes used as a weapon, and as it persistsjpnly in 

 the males, is perhaps useful in contests between rivals. 



Echidna and Proechidna live in rocky regions, are mainly nocturnal 

 in habit, and burrow rapidly, legs foremost. They feed on ants, which 

 are caught on the rapidly mobile, slender, viscid tongue. No traces 

 of teeth have as yet been seen. 



