BRANCH CHORD AT A: CLASS BATRACHIA 301 



always associated with goldenrods and asters and falling 

 leaves. ' ' The tree-frogs of North America lay their eggs 

 in the water on some fixed object as an aquatic plant, in 

 smaller packets than those of the true frogs, and not in 

 strings as do the toads. 



The toads (Bufonidae) differ from the true frogs in 

 having no teeth and in not having, as the frogs do, a 

 cartilaginous process uniting the shoulder-bones of the 

 two sides of the body. The absence of this uniting 

 process makes the thoracic region capable of great expan- 

 sion. There are only a few species of toads in North 

 America, but one of these species, the common American 

 toad (Bufo lentiginosus), is very abundant and wide- 

 spread. It appears also in two or three varieties, the 

 common toad of the southern States differing in several 

 particulars from that of the northern. The toad is a 

 familiar inhabitant of gardens, and does much good by 

 feeding on noxious insects. It is most active at twilight. 

 Its eggs are laid in a single line in the centre of a long 

 slender gelatinous string or rope, which is nearly always 

 tangled and wound round some water-plant or stick near 

 the shore on the bottom of a pond. The eggs are jet 

 black and when freshly laid are nearly spherical. At the 

 time of egg-laying the toads croak or call, making a sort 

 of whistling sound and at the same time pronouncing deep 

 in the throat " bu-rr-r-r-r. " The toad does not open its 

 mouth when croaking, but expands a large sac or resonator 

 in its throat. The toad-tadpoles are blacker than those 

 of frogs or salamanders, and undergo their metamorphosis 

 while of smaller size than those of frogs. When they 

 leave the water they travel for long distances, hopping 

 along so vigorously that in a few days they may be as far 

 as a mile from the pond where they were hatched. They 

 conceal themselves by day, but will appear after a warm 

 shower; this sudden appearance of many small toads 



