l6o VERTEBRATE ANIMALS OF THE UNITED STATES 



tubercles often present on the digits; eggs laid in a long chord of jelly 

 which is usually deposited on the bottom of some shallow pool: nearly 

 ICO species; 15 in the United States. 



Key to the United States Species of Bufo 



ai In the States east of the Mississippi, 

 bi In the northeastern States. 



Ci Profile of snout sloping; back with a single wart to a color 



spot B. americamis. 



c-2 Profile of snout abrupt; back with more than one wart to 



a color spot B. fowleri. 



b*; In the southern States. 



Ci Cranial crests very prominent (Fig. 85) B. terresiris. 



C2 Cranial crests inconspicuous B. quercicus. 



a2 In the States west of the Mississippi, 

 bi In the central western States. 

 Ci Belly spotted. 



di Cranial crests divergent (Fig. 81) B. americanus. 



do Cranial crests parallel B. hemiophrys. 



C2 Belly unspotted B. woodhousii. 



bo In the southwestern States. 

 Ci Cranial crests absent. 



di Parotoid glands small, and oval or round. 



ei Plantar tubercles small B. punctatus. 



t2 Plantar tubercles large, with cutting edges B. compactilis. 



di Parotoid glands large and long, B. debilis. 



C2 Cranial crests present. 



di Cranial crests sharp-edged and high B. valliceps. 



do Cranial crests thick, confluent between the nostrils. . . .B. cognalus. 



ds Cranial crests curved around the eyes B. alvarius. 



bs On the Pacific slope. 



Ci With a light middorsal line; skin rough B. boreas. 



Co Without a light middorsal line; skin very smooth B. canorus. 



B. americanus Holbrook. Common toad (Figs. 81 and 83). Body 

 heavy and squat and variable in color, being usually gray or yellowish 

 brown, more or less mottled or spotted; throat of male black; under 

 parts white, spotted; parotoids elongate and reniform; cranial crests 

 divergent; length 70 mm.; hind leg 85 mm.; female much larger: North 

 America east of the Rockies; northward to Hudson Bay and Great Bear 

 Lake. 



B. fowleri Hinckley. Common toad (Fig. 84). Body rather 

 slender, greenish or yellowish gray in color, spotted or striped with 

 brown; under parts white; throat of male black; parotoids narrow and 

 not reniform; cranial crests parallel; length 75 mm.: central New 

 England to Georgia; westward to Michigan and Texas. 



