144 sd THE VIVARIUM. 
parts of the animal are often of a beautiful green colour, but 
sometimes bluish and sometimes of a slate colour ; the under-parts 
are yellowish-green. There is frequently a whitish band in front 
of the shoulders. The tail is generally rayed or ringed with 
green, yellow, and brown; on the sides there are zigzag, dark 
yellowish-edged markings. The Reptile is uaturally gentle, but 
it is able to give, when frightened or when struggling, a nasty 
wound with its tail if it strikes an unprotected part of the human 
. body. 
The Naked-necked Iguana (J. delicatissima) and the Black 
Iguana (Metopoceros cornutus) should receive the same treatment 
in confinement as that recommended for the Tuberculated Iguana. 
The Naked-necked Iguana differs from J. tuberculata, among 
other things, in the size of some of its scales, in having a rather 
lower dorsal crest, and in possessing ventral scales which are 
more distinctly keeled. The black Iguana may be known from 
its tuberculated relative by its much smaller gular sac and gular 
fold, its longer tail, and black colour. 
The Horned Lizard (Phrynosoma cornutum, Fig. 50) is a very 
extraordinary-looking Lizard; it is also known as the Horned 
Toad, the Californian Toad, the Stagyrite, and the Tapayaxin. 
My own children call it the Lizard which “ dies every night and 
comes to life again every morning.”’ This variety of names, at 
any rate, goes far to imply that the creature is at least remark- 
able and interesting. Though frequently called a Toad, it cer- 
tainly is not one, Luta true Lizard, belonging to the family of 
the Iguanide. I have already mentioned that this family con- 
tains some of the ugliest of Lizards as well as some of the most 
beautiful, and I think anyone would be willing to endorse this 
statement if, for example, an Anolis and a Phrynosoma were 
placed side by side. At first sight it would seem impossible that 
there could be any relationship between them. The one so 
active, smooth, slender, long-tailed, and gaily-coloured ; the other 
inactive (certainly in captivity), rough to an extraordinary degree, 
broad, short-tailed, and soberly-tinted. Both, however, have 
considerable powers of changing colour, and both use this power 
as a means of defence against their common enemies—e.g., the 
former assuming the exact green of the leaves of the tree in 
