Pelobatidae 



rate, these facts are well authenticated : They disappear with never 

 a stray one left behind, and they may not appear again in the 

 same locality for many years. 



They leave the pond filled with eggs — strings of eggs fas- 

 tened to grass blades or stretched from weed to weed. In most 

 of the cases observed, the ponds dried up before there was time 

 for the development of the eggs, and in all cases the devel- 

 opment seemed to be hastened because of the drying of the pond. 

 The eggs hatch in from seven to fifteen days, according to the 

 temperature. 



The tadpoles appear velvety black in water, but when ex- 

 amined closely are rich brown in colour. They are short and 

 stout-bodied, with narrow, spotted tails. In about two weeks 

 after hatching, the delicate thread-like arms appear and the ab- 

 sorption of the tail begins. They leave the water while the tails 

 are still quite long. Like toads, they will drown if they have 

 no opportunity to get out on land. The tadpoles may show the 

 yellow dorsal lines characteristic of the adults even before the 

 front legs appear. 



The first instinct of the little Spadefoots is to burrow. The 

 feet are supplied with the apparatus for digging, although it is 

 not as hard and horny as it becomes later, and so necessitates 

 making the burrow in soft earth. The diminutive creatures have 

 been observed to feed greedily on flies and young spiders. 



One observer records an exodus of thousands of young Spade- 

 foot toads from their native pond. For hours they "trudged" 

 in leisurely fashion up a steep hill, apparently not stopping for 

 food on their way.^ When picked up in the hand, they made a 

 faint squeaking noise. 



The adult Spadefoot is an unintelligent and somewhat un- 

 canny-looking creature — its appearance quite matching its mys- 

 terious habits and underground life. (Fig. 15.) The wide, rounded 

 head bears two extremely prominent eyes set far apart. The ver- 

 tical pupil has a narrow downward-projecting slit at the lower 

 end. The iris has a black triangular indentation at its anterior 

 margin. One-fourth inch behind the eye and about equalling 

 it in size, is a round parotoid gland. 



The skin is smooth, compared with that of the common toad, 



1 Tlie life history of the Hermit Spadefoot is taken from the accounts of various observers cited 

 in Bibliography, pp. 241 to 250. 



56 



