Il6 PROCEEDINGS MANCHESTER INSTITUTE 



value in classification. The plates upon the head are named 

 according to their proximity to the lips, mouth, chin or eyes, 

 and are also of use in classifying, as they vary but little in indi- 

 viduals of the same species. The skin is cast whenever the 

 growing body needs a larger coat. I have seen one shed its 

 skin three times in one season in confinement, and have read of 

 its being done four times under the same circumstances. In na- 

 ture it is probably not cast so often. As the time for shedding 

 the old skin approaches, it becomes dull in color and the eyes 

 assume a milky hue as that portion of the skin over the pupil 

 becomes partially opaque and begins to separate from the eye- 

 ball. For a few days the snake is nearly blind. Finally, by 

 rubbing against some rough substance, the skin is peeled back 

 at the lips, and then by crawling between two sticks or stones, 

 or under something, or even through its own coils, the skin is 

 turned wrong side out and is worked off at the tail, when the 

 ophidian appears in new colors, as bright as the proverbial but- 

 ton. This cast-off skin is stretched out considerably longer 

 than the snake that it covered, and so should not be taken as a 

 correct measure of its former occupant. 



The progression of serpents is remarkable. The ventral 

 plates may be used to push the animal along in a straight line ; 

 they ma 3^ be used a side at a time, when the snake moves with 

 an undulatory movement ; or the bod}^ may be pushed along by 

 the extension of its muscles, which movement alternates vsdth 

 the pulling of the hind part. No snake can jump. The so- 

 called jumping is only the throwing of the forward portion as 

 far as it will reach from its position when coiled. 



The eggs are covered with a leathery envelope which the 

 young snakes rupture by means of an egg-tooth similar to that 

 of a chick. Snakes are both oviparous and viviparous. In the 

 latter the eggs are matured in the parent but are hatched in the 

 oviduct. One curious habit that is ascribed to our water adder 

 (A^. Sipcdo7i) is that of protecting its young by opening the 

 mouth and allowing them to run in. I was always inclined to 

 doubt the accuracy of the observation of those who professed to 



