38 BULLETIN 194, UNITED STATES NATIONAL MUSEUM 



8. Large parotoids present, not in contact with eye, colored like body; 



small toads 9 



Parotoids smaller than side of head 11 



9. Dorsal cranial ridges not or scarcely discernible; if present, represented 



by very low (or discontinuous) elevations or tubercles; lateral head 

 crests better developed; parotoid not widest anteriorly, much longer 



than wide; tibiotarsal articulation to about middle of parotoid 10 



Dorsal cranial ridges strongly developed in adults, surmounted by a 

 continuous line of spiny tubercles; parotoid generally triangular, nearly 

 as wide as long, widest anteriorly; tibiotarsal articulation barely 

 reaches parotoid; 44 mm kelloggi (p. 42) 



10. Toes about one-third webbed; nostril back from tip of snout; preorbital 



and suborbital crests smooth, without tubercles; parotoid as large as 

 side of head; anterior edge of tympanum not strongly elevated; 52 



mm debilis (p. 42) 



Toes about one-half webbed; nostril at extreme tip of snout; parotoid 

 larger than side of head; preorbital and suborbital crests with some flat 

 tubercles; anterior edge of tympanum elevated; 59 mm __ insidior (p. 42) 



11. Parotoids 1% to 1% area of eyelid, in contact or narrowly separated from 



it; tubercles under toes not prominent or numerous; large toads 12 



Parotoid less than eyelid and separated from it; or if larger, very narrow, 

 elongate ; tubercles prominent under toes 13 



12. Parotoid l}i to 1% area of eyelid, touching eyelid; foot less than one-half 



webbed; no specialized tibial gland; tympanum often indistinct or 



covered; straight, heavy supraorbital crests; 95 mm simus (p. 42) 



Parotoid lYs to 1% area of eyelid, very narrowly separated from eyelid; 

 foot two-thirds webbed, larger; one or more specialized glands on tibia; 

 no cranial crests; 110 mm boreas halophilus (p. 43) 



13. Very small toads with narrow elongate parotoids, twice as long as wide; 



cranial crest very low; supraorbital and postorbital crests forming a 



curve; 54 mm canaliferus (p. 43) 



Larger toads; parotoids usually smaller than an eyelid, not long and 

 narrow, usually as wide as long (little more or less) 14 



14. Cranial crests high, weU defined, consisting of a preorbital, supraorbital, 



postorbital, pretympanic, supratympanic; the occipital crest present or 



absent 15 



Cranial crests low, inconspicuous (absent in younger specimens) 20 



15. Occipital crest absent, or occasionally barely indicated; parotoid smaller 



than eyelid, its greatest length equal to or less than eye diameter; 

 large, rather elongate-bodied toads with rather long legs; tibiotarsal 



articulation reaching to tympanum or near it 16 



Occipital crests present 17 



16. Distance between summits of supraorbital ridges greater than width of 



eyelid; pretympanic crest equal to supratympanic; greatest diameter 

 of tympanum not more than two-thirds eyelid; 99 mm__ gemmifer (p. 43) 

 Distance between summits of supraorbital ridges less than width of eyelid ; 

 height of tympanum equals seven-eighths of eye diameter; supratym- 

 panic crest shorter than pretympanic; parotoid about one-half eyeUd; 86 

 mm mazatlanensis (p. 43) 



