Fowler's Toad 



never kidney-shaped. The skin is somewhat less rough, and 

 never has the large warts so conspicuous in the Bufo americanus. 

 The head is less broad, the whole form more delicately moulded. 

 The foot is less broad and thick; the toes more slender. The 

 voices are wholly different, and could never be confused 

 after being heard with even small attention. The time of 

 breeding is different, Bufo fowleri not being able to endure as 

 low a temperature as does Bufo americanus. Two to four 

 weeks after Bufo americanus has appeared in the ponds, and, 

 in fact, after the greater number of this species has returned to 

 land life, Bufo fowleri comes from hibernation. Moreover, the 

 eggs of the latter toad are often arranged in double rows. They 

 never are, as far as reported, in the case of Bufo americanus. 

 There should be no trouble in distinguishing the two toads. 

 The confusion arises in regard to the cranial crests. Those of 

 Bufo americanus are usually like the type for that species (see 

 Fig. 48), but Bufo fowleri varies most remarkably in this 

 structure. The head crests may be parallel or may diverge; 

 may lie close together or far apart ; may be considerably elevated 

 and sharp-edged, or low rounded ridges; may be on a raised 

 occiput or not; and may be fused at their posterior ends, or 

 separated by a groove as in Bufo americanus. The great varia- 

 tion in the cranial crests of Bufo fowleri, Bufo I. woodhousei, 

 Bufo quercicus, and other toads would seem to indicate that this 

 structure cannot perhaps be made so fundamental in classifica- 

 tion as has been thought. 



Since Bufo fowleri differs fundamentally from Bufo ameri- 

 canus, and occupies the same localities, it must be granted full 

 specific rank. 1 



a The closer relationship that must have existed between these two toads in previous ages is 

 shown in the fact that the tadpoles are almost identical in structure. The mouth of the tadpole of 

 B. fowleri is more delicate, the delicacy especially noticeable in the papillae. The tadpoles differ 

 in colour. (M. H. Hinckley, "On Some Difference* in the Mouth Structure of Tadpoles." Proc. 

 Bost. Soc. Nat. Hist., Vol. XXI, pp. 307-314). 



97 



