MISCELLANEOUS NOTES. 835 



white." This description is most probably based on spirit preserved speci- 

 mens in which the colour had faded a good deal with age, or as will be clear 

 from what follows ; the specimens referred to had, or assvnned a nearly 

 uniform grey colour, on being captured ; for the colour of the lizard during 

 life is c^uite different from what has been quoted above. 



Ordinarily the dorsal surface is grey, with five wavy bands of a black 

 colour ; the first band is on the neck. These black stripes are very promi- 

 nent, and hence the grey colour is not very markedly visible at these times ; 

 the bands are rather dark in the middle, while the margins are of a lighter 

 colour. On the lateral sides of the animal, instead of the bands being 

 continuous, there are small dots scattered irregularly. On the head two T - 

 shaped marks, one lying within the other, are to be seen ; while the ground 

 colour is also darker than the rest of the body. On the fore limbs there are 

 six bands each, while on the hind limbs there are seven each, and on the 

 tail there are eleven. All these hands have a wavy outline, specially well 

 marked on the posterior side. {Fig. 1.) The ventral surface is yellowish. 

 With the change of colour, the lizard is of the colour described by Boulenger, 

 except that the ventral surface is yellowish. 



The black colour of the lizard is due to black pigment corpuscles. The 

 pigment corpuscles are not confined to the dorsal surface or the lateral 

 sides only, but are found ventrally as well. The corpuscles which are 

 found in the dermis are star-shaped {Fig. 2), sending out long processes 

 from all sides ; the processes resemble very much the pseudopodia of an 

 amoeha, and are retractile like them ; in fact the whole corpuscle is very 

 much like an amoeha, sending out or retracting its pseudopodia under 

 various stimuli ; the change of colour of the animal is due to the sending 

 out or retracting of these processes. The number of these corpuscles on the 

 dorsal surface is about thirty- two in each scale, while on the ventral 

 surface it does not exceed eight. 



A few experiments were also tried to ascertain the changes of colour as 

 brought about by the effects of temperature, light, darkness, and excite- 

 ment. These are described separately under various headings : — 



/. Temperature. About the first week of March, when these lizards 

 assume their activity after a period of rest, and come out of their winter 

 hiding places, the colour of the lizards is grey, but with the change of 

 season one finds a gradual change taking place in the colour of the lizard 

 as well. So that about the middle of May, the lizards show light stripes 

 of a black colour on their bodies. About the beginning of June, the stripes 

 become of a much darker colour, and now one seldom sees a grey-coloured 

 lizard. In the Punjab, the summer season begins about the beginning of 

 April, and the shade temperature which never goes higher than 70" F. 

 during the winter, rises up to 120° F. in June, this shows clearly that the 

 change in the colour of the lizard goes hand in hand with the rise of tem- 

 perature. The lizards are of a lighter colour early in the morning, but 

 assume a darker colour with the advent of the day. Moreover it was 

 observed that the lizards became of a darker colour, when the glass jar 

 containing these was kept in direct sunlight ; to exclude the light-factor the 

 jar was wrapped up in a black cloth. The lizards assumed their normal 

 colour on being brought came into the room and the jar cooling down to the 

 normal room temperature. The change of colour however is neither so 

 sudden, nor so abrupt as to be considered due to a change in the environ- 

 ment, but comes about very gradually. 



II. Light and darhness. Lizards exposed to a strong light, as for 

 example the direct sunlight, become of a darker colour. Experiments were 

 tried in which half of the body of a lizard was exposed to the strong light, 

 while the other half was in darkness : in these cases the lizards became of 



