36 THE VIVARIUM. 
and the like are suitable, and in the branches of which these 
beautiful Snakes will climb, bask, and sleep. 
Fig. 23 represents an Aquarium turned into a case for Batra- 
chians. In such a Vivarium as this several different kinds of 
Fig, 24.—FrRoG-Bir (Hydrocharis morsus-rance). 
aquatic or semi-aquatic plants can be grown. The gravel is made 
to slope from about 4in. deep at one end to about din. deep at the 
other. The water should be allowed to stand at adepth of about 
3in. There will be then a uniform depth of some 3in. of water 
in the Vivarium, though there will seem to be, at one end only, 
