TROPIDONOTUS 159 



The Grass-snake gets on very well with the 

 Adder, to whose venom it is immune. 



It has more than once been met with swimming 

 in the sea, and a case is reported of one having been 

 captured in the open sea twenty-five miles from the 

 nearest land, no doubt carried away by the current, 

 but still perfectly lively. 



The hibernating season is spent in holes in walls 

 or at the root of trees, often under manure-heaps, 

 and the awakening occurs in March or April, soon to 

 be followed by the first exuviation and the pairing. 



Reproduction. — Pairing takes place in April or in 

 May, according to the climate, and the eggs are 

 laid between June and August, the young emerging 

 six to ten weeks later. It is probable that a second 

 pairing occasionally takes place in the autumn, as 

 eggs have sometimes been found in manure-heaps 

 at the end of winter. Females do not breed until 

 about 2 feet long, males a little sooner. The eggs 

 number 11 to 48, according to the size of the 

 female, and, after being produced in a string, stick 

 together in a mass, without any regularity. 



The eggs measure 1 to 1^ inches in length, and 

 when newly laid are about once and a half as long 

 as broad. They often contain at the time they are 

 produced a more or less developed embryo. They 

 are sometimes laid in recesses in walls, in heaps 

 of sawdust near sawmills, under dead leaves, but 

 preferably in manure, for which purpose females 



