MATES. 



171 



knee to the level of the sacrum, and stretching it out 

 again, he passes it, toes first, into the egg-mass; the 

 other limb follows in like manner. These movements 

 are repeated several times, and accompanied by one 

 or two seminal ejaculations. Thus the strings of eggs 

 come to be fastened round the legs, where they will 

 remain until eclosion. All the time this operation has 

 lasted, about ten minutes, the female has remained 

 motionless, still connected with the eggs by the last 

 elastic filaments from the oviducts. These two threads 

 stretch to a length of 4 to 12 inches before breaking 

 when the pair separates. 



Thus laden, and yet so little impeded in his 

 movements as to occasionally resort again to hymen 

 during the nursing period, and successfully add 

 on a second burden, the male retires to his usual 

 retreat, Q-o'mg- about at night in order to feed him- 

 self and to keep up the moisture of the eggs, even 

 resorting* to a short immersion in the water during 

 exceptionally dry nights. The development within 

 the egcr takes about three weeks, sometimes a little 

 less, often a little more. The male enters the water 

 with his burden ; the larva?, in the full tadpole con- 

 dition, measuring 14 to 1 7 mm., bite their way through 

 the tough envelop, which is not abandoned by the 

 father until all the young are liberated. 



The tadpole is found in spring and summer, at all 

 stages of development, in small reservoirs, cow-ponds, 

 flooded quarries, pits in brick-fields, &c. The tadpoles 

 of the late broods hibernate under the ice, concealed 

 in recesses but not torpid. Some specimens, at least 

 in confinement, remain nearly two years before trans- 

 forming, but, as a rule, larva? born early in the spring 

 accomplish their metamorphosis within three to five 

 months. The duration of the larval life varies, how- 

 ever, in individuals of the same brood; and as such as 

 have not sufficiently developed their limbs to take to 

 the land in the autumn have necessarily to post- 

 pone the metamorphosis until the following spring, it 



