PHRYNOSOMACORONATA. 67 



margin from the anterior to the posterior extremities. The scales on the thorax 

 and abdomen are large, rhomboidal and smooth, terminating posteriorly in a point. 



The tail is large, broad, and flattened at the root, but soon becomes smaller, 

 is depressed in its whole length, and covered above with scales and pointed 

 tubercles, as on the back; and below, with large rhomboidal scales, elongated in 

 points posteriorly. On each lateral margin of the tail is a very remarkable range 

 of large trihedral flattened spines, which gives to the tail a strong and regularly 

 serrated border, unlike any other of this genus that I have observed. 



The anterior extremities are well developed, and protected in front by large, 

 elongated, rhomboidal scales, carinated and pointed, even to the roots of the nails; 

 their under surface is covered with small, smooth, rhomboidal scales; there are five 

 fingers, distinct and slender, each with a short and curved nail. The posterior 

 exti'emities are but little larger than the anterior, and are covered in the same 

 way, but have strong spines along the superior and posterior part of the thigh. 

 The toes are five in number, large, distinct, and furnished each with a short and 

 curved nail. On the under surface of the thigh is a range of sixteen or eighteen 

 pores. 



Colour. The head above is light brown, with a few dusky blotches; the 

 upper jaw is grey. The three inferior spines that surround the head are light, and 

 the two central spines are dark chestnut. The ground of the colour of the neck 

 and body above is pepper-and-salt grey, with a lighter vertebral line from the 

 occiput to near the extremity of the tail, but frequently interrupted by transverse 

 dusky bars; nor is it perfect in other parts, as it contains several spines, which are 

 all dark; on each side of this line at the neck is an oblong dark chestnut blotch, 

 reaching to the shoulders, broad before and narrow behind. Behind these are 

 four bands with irregular margins, which traverse completely the vertebral line, but 

 are there less evident. The throat and abdomen are silvery-white, marked with 

 large dusky blotches, frequently confluent. The tail is coloured like the back 

 above, but is more completely banded, especially towards the tip; its inferior 



