5 % 
room x. the jaw-bone, and mostly lobed and indented. 
They are all found in America. 
Some of the Iguanas have a compressed dew¬ 
lap under the throat, and the back crested; 
among which are the common Guana ( Iguana 
tuberculata), which is used both for food and 
medicine in the West Indies, and the banded 
Guana ( Iguanafasciata ). 
Other species of this genus have only a fold 
across the throat, as the Spiny-tailed Guana 
(Iguana Acanthura ), Clouded Guana ( Iguana 
nubilo ), Sword-tailed Ophyessa ( Ophyessa super - 
ciliosa ), Umber Ophyessa {Ophyessa plica) , Col¬ 
lared Tropidurus ( Tropidurus torqualus}, Keeled 
Leiocephalus ( Leiocephalus carinatus ), Northern 
Tropidolepis ( Tropidolepis undulaius ), Collared 
Troj)idoieipis{Tropidolepis torqualus ), Douglass’s 
Toad-Lizard ( Phrynosoma Douglassii , and 
Blainville’s Toad-Lizard ( Phrynosoma Blain- 
villii ). These animals are very quarrelsome, 
and fight with great ardour when they meet. 
In other species of Guana, the ribs surround 
the body, like those of the Chameleon, and like 
them, these animals have the faculty of changing 
their colour with great rapidity. Three of the 
genera belonging to this division of the Guanas 
are each marked with very striking characters: 
the first, the Basilisk ( Basiliscus ), has a com¬ 
pressed hood on the back of the head, and a 
fin-shaped 
