Choose the description that best fits the animal of interest.  If none
fit go back to question 16.

18a.  cranial crests fused into raised ridge between eyes, not British
Columbia

                    Bufo hemiophrys (Canadian Toad)

18b.  cranial crests L or V shaped, diverging behind eyes, large dark
blotches with dark border, extreme southern prairies only

                    Bufo cognatus (Great Plains Toad)

18c.  no cranial crests, Alberta, British Columbia and Yukon only

                    Bufo boreas (Western Toad)