The American Toad, Bufo lentiginosus americanus LeConte. 33 



THE MATURE TADPOLE. 



Length of body 1.3 to 1.7 in the length of the tail, average 1.49. 

 Width of body in its own length 1.25 to 1.7, average 1.52. Nostril 

 nearer the eye than the snout. Eye usually nearer the snout, but 

 occasionally equidistant between the snout and the spiracle. Distance 

 between the nostrils contained in the interorbital space 1.2 to 1.8, 

 average 1.6; in mouth 1.4 to 2.2, average 1.76. Spiracle sinistral, 

 1.3 to 1.8 nearer the base of the hind legs than the snout, average 1.54. 

 Anus median. Depth of tail in its own length 1.25 to 2.7, average 1.97. 

 Mouth contained in the interorbital distance 0.77 to 1.00, average 0.92. 

 Greatest length, 28 mm. Greatest length of body, 10 mm. Greatest 

 length of tail, 18 mm. Greatest depth of tail, 5 mm. 



Coloration of body (Plate ix, Fig. IK) : The ground color is a very dark 

 brown or black overlaid with many fine gold and silvery spots, these 

 aggregated in a few places. The venter is like the back, but the aggre- 

 gates of bright spots are more silvery and more or less iridescent 

 (coppery) . The muscular portion of the tail is dark, like the back, with 

 a few gold-spotted areas. The crests are cloudy transparent. 



Mouth-parts (Plate vm, Fig. 6) : On the upper lip are two rows of 

 teeth, a marginal row and a series of lateral teeth, the outer ends of 

 which do not extend beyond the end of the marginal row. The median 

 space between the lateral rows is almost equal to the length of a lateral 

 row. Between the lateral series and the marginal series there is usually 

 a dark line of color. Three straight non-wavy rows on the lower lip ; 

 the third row is long and forms the lip's margin, which has no papillae 

 along its median portion. In 90 specimens, there were few variations 

 from the normal. In only two instances was the third lower absent, 

 and in two others it was faint. Rarely, the second and sometimes the 

 first lower rows are discontinuous in the middle or divided into several 

 parts. In the upper labium the marginal fringe was broken but twice. 

 In one instance the lateral row was almost absent on one side; and in 

 another case the lateral series almost bridged the median gap. 



THE LARVAL PERIOD. 



This period ordinarily covers from 50 to 65 days. In 1907 eggs were 

 first laid April 30 in one pond, where transformed individuals were 

 first noted July 5, 66 days later; in another pond, 51 days were required 

 for the species to reach transformation. In 1906 the first eggs were 

 laid April 22, and the first larvae transformed June 23, 62 days later. 

 In 1908 <i period of 64 days was secured. In 1911 the transformations 

 came at periods ranging from 41 to 60 days. 



THE TRANSFORMATION. 



This is usually the first Anuran of the season to transform. When 

 transformation is taking place, the shores of some ponds are black 

 with myriads of little toads, their numbers being particularly notice- 



