142 THE EEPTILES OP EGYPT. 
arranged in transverse series with dark interspaces ; black bands pass down to the 
belly from the sides and meet on the mesial line below, and similar lines occur on the 
under surface of the neck and on tbe limbs, the yellowish intervening areas having 
many black spots. The upper surface of the limbs black, with yellowish spots, as on 
the sides. General colour of the under surface yellowish. In the adult the markings 
of the young become very obscure. The general colour is olive brownish above with 
dark reticulations, the yellow spots of the body and limbs and the dark markings of 
the belly and limbs being more or less present. 
It attains to 170 centimetres or more in length. Although more or less aquatic in 
its habits it is frequently seen hunting for its food along the banks of the Nile, and is 
met with in the irrigated fields, but never in the desert. It is carnivorous in its habits, 
and is said to live largely on fish, to pursue the young of the crocodile, and also to eat 
the eggs of that animal. Little reliable information, however, has yet been placed on 
record regarding the habits of this lizard. From the strongly carnivorous instinct 
which it manifests in confinement, eating rats and mice with avidity, it probably preys 
on the field-rat, Isomys, the burrows of which are so plentiful along the banks of the 
river and canals, and may likewise devour such lizards as Mabuia quinquetceniata and 
Chalcides ocellatus, which are found in similar situations. When surprised on the 
banks of the river it at once betakes itself to the water. It appears to be more 
numerous in Upper than in Lower Egypt. It is distributed throughout Africa, except 
in the region to the west of the Nile and to the north of the Congo, Niger, and 
Senegal rivers. 
The native name of this lizard is jA\ ,\,.=tuaral el nahr, or waral of the river. 
In this species two slight prseanal eminences are occasionally present in both sexes, 
immediately before the cloacal opening, occupying the position of the prseanal pores of 
the other lizards. They are present in specimens from different parts of Africa, e. g. the 
island of Lagos, Port Elizabeth, Lake Nyassa, Condo (Quanza), Boluma (Senegambia), 
Lamu (E. Africa), and Ashantiland. The smallest of all the specimens in the British 
Museum, from the Quanza, is very instructive. The apical pores of the scales anterior 
to the cloacal opening are larger than in any other part of the body, and one or two 
are larger than the others immediately around them. These enlarged pores are 
restricted to the centre of each prseanal eminence, but no one is more differentiated 
than another. On the other hand, in a specimen from Port Elizabeth there is a 
well-developed pore on each side of the mesial line, with some small pores around it. 
Much the same condition is occasionally met with in V. griseus. 
