. ACANTHOSAURA CORONATA. 149 



each shoulder. Ventral scales small, strongly keeled ; tAventy-four longitudinal series across 

 the breast, between the axils. The scales in the prseanal region not larger than tliose of the 

 belly. Tail slightly compressed at the base, with all the scales keeled ; those on its lower 

 surface are longer than broad, very strongly keeled, each keel terminating in a small spine. 

 Limbs of moderate length ; the hind limb extends to the temple, if laid forwards. Toes with 

 keeled scales below ; the fourth toe (measured from the heel) is as long as the head ; the 

 third is one-third shorter. Greenish brown, with indistinct, roundish light spots ; throat of 

 the adult blackish brown, with an orange-coloured streak along the middle. 



Two specimens were collected by Mouhot, at Chartaboum, on the coast of Siam ; the larger 

 is 13 inches long, the tail measuring 8; the other is only half that size, and has the post- 

 orbital spine and the nuchal crest Avell developed, though comparatively lower. 



xiCANTHOSAURA CORONATA. (Plate XIV. fig. E.) 



Acanthosaura coronata, Gilnth. Proc. Zool. Soc. 1861, April 23, p. 187. 



Back and sides covered with small, imbricate, smooth scales, the tips of which are slightly 

 turned towards the dorsal line ; larger keeled scales are scattered between the small ones. 

 A low crest formed by triangular scales runs from the nape to the root of the tail, where it 

 is very indistinct. The supraorbital edge is very prominent, sharp, serrated behind ; a very 

 short conical spine behind the supraorbital edge, separated from it by a deep incision. 

 Another short spine on each side of the neck, midway between the tympanum and nuchal 

 crest. Tympanum neai-ly as large as the eye. No gular sac ; an oblique fold before each 

 shoulder, not extending across the throat. Ventral scales keeled ; eighteen longitudinal 

 series across the breast, between the axils ; pra;anal scales not larger than ventrals. Tail 

 slightly compressed at the base, with all the scales keeled ; those on its lower surface are 

 longer than broad and very strongly keeled. Limbs of moderate length ; the hind limb 

 extends to the eye, if laid forwards. Toes with keeled scales below ; the fourth toe (measured 

 from the heel) is as long as, or shorter than, the head ; the third is one-third shorter. The 

 ground-colour of the male is grey, of the female brownish red ; irregular dark-brown bands 

 across the back and the legs. A yellowish-olive band edged with black across the crown, 

 from one superciliary edge to the other ; an oblique, short yellow band, broadly edged with 

 brown, from below the orbit to the angle of the mouth. Four short brown streaks radiate 

 from the upper eyelid over the lower surface of the prominent superciliary edge. 



Several specimens have been collected at Chartaboum together with A. armata and A. capru. 

 An adult pregnant female is 1 inches long, of which one-half is taken by the tail ; we have 

 figured it on Plate XIV. 



