GERRHOSAURUS TYPICUS. 
lower lip four, the last but one much the largest. Scales of back and sides 
quadrangular, arranged in transverse rows, and each strongly carinated ; 
the scales of the upper and lateral portions of the tail are of the same 
form as those of the back, similarly arranged and carinated. Lateral dupli- 
cature slightly developed, space between rami of lower jaw anteriorly with 
four large plates, the two first the smallest ; throat behind these and the 
breast coated with six-sided smooth imbricate scales, their greatest width 
transversely, and all arranged in longitudinal rows. Plates of the belly 
arranged in transverse rows, ten in each, of a quadrangular form, and 
each row lying over the base of the one behind it. Preanal plates, 
three in a single row, the middle one triangular, and its apex directed 
backwards. Scales of under surface of tail smooth, broadest at base 
tapered towards point, which is slightly rounded. Fore legs coated 
with smooth imbricate scales more or less six-sided ; hinder legs anteriorly 
and interiorly covered with scales of the same description but larger; 
posteriorly the scales are triangular and strongly keeled. Femoral pores 
sixteen, large, and prominent. Soles of the feet covered with very small 
somewhat oval scales. The toes of the fore feet short and slender, the 
innermost one very short, the second considerably longer, the third the 
longest, the fourth a little shorter than the third, and the outermost rather 
longer than the innermost. The third and fourth toes of the hinder feet, 
reckoning the great or inner toe one, are much longer than those of the fore 
feet, and the third exceeds considerably in length the fourth ; the second and 
outermost toes are also much longer than the corresponding ones of the 
fore feet. 
DIMENSIONS. 
Inches. Lines. 
Length from the nose to the base of 
the tail 4 e 
of the tail 6 6 
from nose to meatw ex ter mu 0 9 
Indies. Lines. 
Length from nose to base of fore legs 0 11 
Distance between fore and hinder legs 3 0 
Length of fore legs to base of toes ... 0 .9 
hinder legs to base of toes ... 1 2 
The colours of the two sexes nearly the same. 
The only specimens of this species which I possess were procured on the sandy plains 
wdiicli occur immediately to the south of the mouth of the Orange River. Over the sand of these 
plains they run with such extraordinary rapidity, that it is almost impossible for the eye to 
follow them in their flight. The instant they are discovered they seek a place of concealment, 
and that they generally find in the loose sand which is commonly found accumulated under the 
shrubs with which the district is furnished. In this sand they burrow with amazing rapidity, 
and it requires an experienced eye to trace their course in it, though that is seldom far below the 
surface. 
