CHECKLIST OF THE AMPHIBIA OF MEXICO 39 



17. All cranial crests thickened; occipital crest arising from highest point of the 



supraorbital crest and continuous with it, converging more or less pos- 

 teriorly; belly sulphur yellow with or without some blackish spots or 

 flecks; parotoids longer than wide, occasionally a little larger than eycUd; 

 postorbital and supraorbital crests present; supratympanic crest heavier 



than and about as long as pretympanic; 80 mm cristatus (p. 44) 



Cranial crests narrow, not conspicuously thickened; occipital crest lower, 

 not arising from highest point of supraorbital crest and not continuous 

 with it; supraorbital and postorbital crests forming a continuous curve; 

 bellies not yellow _ _ _ 18 



18. Parotoids about size of eyelid, nearly transverse, broader than long; 



supratympanic crest shorter than pretympanic crest; subartlcular 

 tubercles normally undivided under digits (rarely the distal on third 



finger divided); 73 mm nayaritensis (p. 44) 



Parotoids a Uttle larger than eyelid, robust, diagonal, longer than wide 

 (rarely subcircular) 19 



19. Parotoid robust, smooth, diagonal, longer than wide, outer edge rounded; 



no linear series of enlarged warts on sides of body; one or more subartlcu- 

 lar tubercles under two outer fingers and tubercles on three outer toes 

 double or bifid; dorsal tubercles all rather larger; 75 mm., coccifer (p. 44) 

 Parotoid rather flat, often differently colored than surroundings, yellowish 

 or brownish, outer edge nearly straight; a linear series of enlarged warts 

 on sides of body; dorsal tubercles proportionally smaller; 100 

 mm valliceps (p. 44) 



20. Supraorbital and postorbital crests together forming a curve; space be- 



tween supraorbital crests less than width of an eyelid; a small supra- 

 tympanic crest, less than pretympanic; sexual dimorphism in markings; 



78 mm marmoreus (p. 45) 



Supraorbital and postorbital crest forming angle 21 



21. Crests form obtuse angle; the supratympanic crest absent, leaving paro- 



toid in contact with the postorbital crest; no divided tubercles on hand 

 or foot; sexual dimorphism in markings; large blotches; interorbital 



width equal to an eyelid; 66 mm perplexus (p. 45) 



Supraorbital and postorbital crests form a right angle (or less) if crest is 

 evident (often very low or not discernible) ; not sexually dimorphic in 

 markings; usually uniform olive or brown-olive with small brick red 

 spots which fade; head flat; interorbital width much greater than an 

 eyelid; 80 mm punctatus (p. 46) 



BUFO ALVARIUS Girard 



Bujo alvarius Girard, in Baird, Report on the United States and Mexican 

 Boundary Survey, vol. 2, Reptiles, 1859, p. 26, pi. 41, figs. 1-6.— Kellogg, 

 U. S. Nat. Mus. Bull. 160, 1932, pp. 31, 35-40, fig. 4, and pi. 1. 



Type.~Two cotypes, U.S.N.M. Nos. 2571, 2572 (so designated by 

 Kellogg) ; the first specimen probably lost. 



Type locality. — Valley of the Gila and Colorado Rivers. 



Range. — Central Arizona southward through Sonora, westward to 

 southeastern California (Imperial County). Reported from Sonora: 

 Guadelupe Canon, Quitovaquito, Caj6n Bonito Creek, Santa Ana, 

 Puerto, Hermosillo, Guaymas, La Posa (10 miles northwest of Guay- 

 mas), Alamos, Guirocoba. 



