190 JOURNAL OF THE TRINIDAD 



centre can be seen the terminal portion of the seventh segment 

 which will eventually become the last one. It has also been 

 observed I eat h have been formed in several of the 



rattles within the last few months; especially is this the case 

 on the under surface and there are general symptoms of 

 disintegration in that the older pieces and those furthest 

 removed from the tail are much looser than those which are 

 the result of recent exu\ i . The snake has a splendid 



appetite and gets plenty of food, consequently observations on 

 the growth and decay of the rattle are conducted under most 

 favourable conditions. It is noticeable that as the period of 

 sloughing draws near the new segment which is of a bluish 

 black colour, can be seen growing out from underneath the 

 scales and pushing the last formed rattle out. In this con- 

 nection it may be interesting to note that a fortnight ago I 

 received a specimen of another crotaline — Lachesis muta. This 

 snake is now about to change her skin and I observe that the 

 base of the caudal spine is dark coloured just as it is in the basal 

 segment of the rattle of C. horridus. As the time approaches when 

 the snake becomes temporarily blind the new rattle is pushed right 

 out and the scales which covered it can be seen attached to it, 

 presenting a withered, yellowy-whitish appearance, their free points 

 being somewhat raised. These disappear in time and on the last 

 occasion ! searched the false' bottom of the box in order to recover 

 them if they had dropped. I only found two portions of scales and 

 I could nol say positively whether these had fallen from the new 

 segment of the rattle or not. After the skin is cast the new 

 segment gradually assumes a pale, yellow colour which subse- 

 quently changes into the general hue of the majority of the 

 segments. About the 20th October last the snake appeared to be 

 going to change, and the eyes became pale blue as they always 

 do at this period, but no sloughing took place. Again at Christ- 

 mas time were similar indications observed, but were followed by 

 no exuviation. The change, however, was effected about 

 the first of the present month and now there is not only the new 

 segment but another one which is forming and pushing the new 

 one out. The box is kept near a window and people are con- 

 stantly passing, but it is very rarely that the snake springs his 

 rattle, in fact it is only after considerable teasing that he can be 

 induced to do so at all. The time when he most uses it, is when 

 he is swallowing a large rat, when, if disturbed, he keeps up a 

 continuous and very loud whirring noise. The reason for this, 

 I imagine, is that when the rat is half swallowed the snake 

 feels that he is in a defenceless position as he could not readily 

 either disgorge or swallow the rat and while his mouth is so full 

 he would be utterly unable to use his fangs. He therefore 

 springs his rattle as much to say : "look here, you know I am a 



