696 THE AMERICAN NATURALIST.  [Vou. XXXIV, 
Bronn and Balfour state that the tail is absorbed before hatch- 
ing, and Bronn has implied, as already mentioned, that the 
hatched young remain for a time on the parent's back. If 
these statements be true, and if it were also true that the tail 
assumes the function of respiration, then the animal would be 
deprived of the embryonic breathing organ some time before 
it escapes from the cell on the parent’s back. 
Alytes obstetricans 1 is unique among European frogs in not 
laying its eggs in water. It occurs in various parts of Europe, 
such as the Rhine region in Germany, the neighborhood of 
Marbourg, Paris, and Liège. It has been said that it lives 
only in regions of hilly ground, where there are clear springs ; 
but Cope (85) records that it is common in dry places near 
Berlin. The frog digs skillfully, and remains underground by 
day, but at night it is active in the search for food. 
The eggs are laid from March to June (according to locality), 
in a double string of gelatinous substance. The male loops the 
eggs about its hind legs in the form of a figure 8, and thus 
carries them, for about three weeks, when the young have 
reached a stage of development far beyond that of the typical 
tadpole at the time of hatching. At the end of the period 
the male takes the eggs to water, and there the tadpoles leave 
the egg-membrane, and at once swim about actively. They 
are said to winter in the tadpole stage, although Claus (66) 
has affirmed that the metamorphosis is completed in a month. 
When the tadpole leaves the egg, the external gills are already 
reduced, and the internal gills are fully developed ; the oper- 
cular opening is median ; the tail is ready for swimming ; me 
lungs are developed ; the horny jaws, teeth, and fringed lips 
are formed (these are said to appear later than in the ordinary 
frog) ; the intestine is coiled, and the liver is present ; the head 
kidney is in process of degeneration, and the mesonephros par- 
tially developed ; the legs are not formed. It has been sug- 
gested that the lungs are used before hatching, because alr 
bubbles are given off as soon as the tadpoles reach the water. 
1 A complete account of Vogt’s ('42) article is not given here. Gasser (82) 
also describes details not mentioned here, especially in regard to the blastopore 
the germ layers, and the development of the pronephros and kidneys. 
