252 THE VIVARIUM. 
are one or two pre-oculars and three post-oculars ; the labials, 
which are eight or nine in number, do not touch the eye, owing to 
the interposition of several smaller shields; the scales are smooth, 
and arranged, generally, in twenty-seven rows, the ventrals 
number from 222 to 258; the sub-caudals are in from 77 to 107 
pairs, and the anal scute is divided as a rule, though occasionally 
entire. The ground-colour of the upper part of the Snake, which 
varies, is generally reddish- or yellowish-brown, marked by a 
series of large, dark spots along the back, and a series of smaller 
spots on the sides, alternating with the dorsal ones. Sometimes 
these spots are so large as nearly to obscure the ground-colour, 
and those on the tail join and form three longitudinal bands. 
The head, especially of young specimens, is marked with trans- 
verse lines. The under parts are yellowish or reddish, either 
uniform or thickly dotted with black. 
The Horseshoe Snake may be bought in this country for from 
6s. to 9s. It should be kept in captivity, under the conditions 
recommended for the Dark Green Snake (Z. atrovirens, Fig. 70). 
It will feed upon young mice, and sometimes upon lizards. 
Z. hippocrepis is a native of Spain, Portugal, Sardinia, 
Morocco, Egypt, and Palestine. It grows to a length of about 
4ft.; of this the stoutish tail measures nearly 10in. 
The South American Rat Snake (Spilotes pullatus or variabilisy 
is a beautiful, active, and curious-looking reptile. In its native | 
country it is known as the Crebo; here it is sometimes called the 
Wasp-snake, owing to its colouring. It is not so easily tamed as 
the Indian Rat Snake (Z. mucosus), but, like that Ophidian, it is 
occasionally domesticated (so called) in its own country because of 
its usefulness in the destruction of rats and mice, and even of 
venomous Shakes. It has the habit of making, when excited, a 
curious rattling ncise with its tail; hence its rather common 
name of ‘‘rat-tail.”’ 
S. pullatus possesses pointed scales, which are both strongly 
keeled and imbricated. Its moderately-sized eye has a round 
pupil. It has either a very small loreal or none at all; one 
pree-ocular and two post-oculars ; scales arranged in sixteen rows (an. 
even number -is unusual); ventrals numbering from 198 to 232 ; 
sub-caudals in from 90 to 120 pairs, and an anal scale which is 
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