MEXICAN TAILLESS AMPHIBIANS 



23 



such extreme types is apparent. Additional material may show that 

 these spade-foot toads with skins grading from relatively smooth to 

 warty are separable into at least two groups, and that a more satisfac- 

 tory disposition of this puzzling question will result from the allocation 

 of those taken along the northern border of Mexico to the subspecies 

 hammondii and those with unusually warty skins from farther south 

 to the subspecies multiplicaius . 



The spade-foot toad may be very abundant wherever it is found, 

 though it may escape observation because of its nocturnal habits. It 

 is commonly assumed that it remains in its burrow most of the year 

 and that it comes out only to deposit its eggs in June and July in 

 pools formed by heavy rains. The spade-foot makes circular holes 

 in the ground near the bases of shrubs and clumps of weeds, and yet 

 in very sandy soil it is very difficult to find the place where it has 

 burrowed, for in most instances it appears as if the hole has been 

 pulled in after the toad. After the breeding season is over, these 

 toads seem to take more pains in constructing their burrows, as they 

 are well-rounded inside and resemble somewhat an earthen jar with a 

 narrow top. The surface around the neck of the burrow is often quite 

 sticky when the spade-foot is discovered inside. In Montana during 

 June, 1916, I found that these toads made their appearance after 

 midnight on dark nights, and when hunted with a flash light they 

 burrowed from sight in a very short time. The time from the laying 

 of the eggs to the transformation of the tadpoles and their leaving 

 the water does not exceed 30 days. This rapid development is ne- 

 cessitated by the tendency of the breeding pools of rain water to dry 

 up very quickly. 



This spade-foot toad can be distinguished almost instantly by its 

 trim and neat body appearance, by its moist and usually warty 

 skin, if it has not been hopping about long enough to fill the pores 

 with fine sand and dust, and, like its relatives, by the catlike vertical 

 pupils of the eyes. In life the upperparts are usually olive-colored 

 with splotches of black or purplish black, and with orange-red tubercles 

 scattered over the skin. 



Specimens examined. — Seventy -one, as follows: 



Scaphiopus hammondii multiplicatus 



Museum 



Catalogue 



No. 



Num- 

 ber of 

 speci- 

 mens 



Locality collected 



Date collected 



By whom collected or 

 from whom received 



U.S.N.M 

 Do... 

 Do... 



M.C.Z.... 

 Do... 



62253 

 21801 

 26597 



10038-39 

 8363-66 



Sonora: 

 Nogales 



Sonoyta 



Chihuahua: Meadow Valley. 



Tamaulipas: Miquihuana 



DuRANGO: Durango (streams 

 near city). 



July 27, 1919 

 Jan. 20, 1894 

 July 18, 1898 



1924 

 1921 



F. J. Dyer. 

 E. A. Mearns 

 H. H. and C. S. 



ley. 

 W. W. Brown. 

 P. Townsend. 



