when the alarm goes off in this position the garters always move a little, for the vibration is communicated to the wood and can be plainly felt with the finger-tips; but when the clock is on the cloth-covered table close by and not in contact with the wood on 
Fig. 3.—Skull of Poisonous Snake. which they lie, they never give a sign of having heard it.
When I lived on the island of Trinidad, I had a large collection of West Indian and South American serpents which it was necessary to feed on animals of many different species. It was always noticeable that neither boa, viper elaps, nor coluber ever gave the slightest heed to the voices of these, while at sight of the moving prey they manifested very evident signs of recognition. Snakes as a rule are very timid, and as I often had visitors at feeding time, it used to be necessary to warn them that any stirring about of arms or legs would be sure to delay the dinner; but no restriction was ever needed to be placed on conversation, except that the turning of the head was forbidden—each had to talk straight to his front, no matter whom he addressed.
During the past four or five years I have hunted extensively over the woods of northern South America, from the Bay of Panama to the Delta of the Orinoco, often alone, sometimes with others. Now, when I had company it would be frequently necessary to call on their assistance in capturing some of the long, swift-running snakes. If one of these were discovered some distance off, resting close by a fallen tree, it was my method to go round to the other side of the old trunk and come up unseen, often within a yard of him. There I would shout directions to my friends, sometimes at the top of my voice, where to post themselves and where to head him off. This shouting never caused the snake to stir; but should I show the rim of my hat moving up even a hand's breadth over the intervening trunk, he would be off like a racehorse; for the eyes of a serpent, though dull to note form and color, are exceedingly quick to detect motion.
Now, it may be mentioned that snakes have no external ears, their heads being entirely covered, like the rest of the body, with a tough and scaly skin. Yet in how far they may be able to
