CHECKLIST OF THE AMPHIBIA OF MEXICO 35 



Genus SCAPHIOPUS Holbrook 



Scaphiopus Holbrook, North American herpetologj', ed. 1, vol, 1, 1836, p. 85. 

 Spea Cope, Joiirn. Acad. Nat. Sci. Philadelphia, ser. 2, vol. 6, 1866, p. 81 

 (genotype, Scaphiopus bombifrons Cope). 



Genotype.- — Scaphiopus solitarius 'H.o\hTOok= Scaphiopus holhrookii 

 (Harlan) . 



Range. — New England and British Columbia southward through 

 Mexico as far as Cape San Lucas and the southern edge of the plateau 

 in Oaxaca. 



Species. — Eight forms are recorded, two of which are subspecies of 

 S. holhrookii; three occur in Mexico. 



KEY TO MEXICAN SPECIES OF SCAPHIOPUS 



1. Width of an eyelid equal to or very slightly less than the interorbital 



space; eye as long as the snout or a little shorter; skin of head somewhat 

 involved in the cranial ossification in fully adult specimens; dorsal 

 markings a broad reticulum of dark brown or black on a cream or light 



tan background; 74 mm couchii (p. 35) 



Width of an eyelid 1^4 to lYz of the interorbital distance; length of eye 

 1^ to nearly twice the length of snout; skin of head not involved in the 

 cranial ossification; dorsal pattern not a dark reticulation on a lighter 

 background 2 



2. Hand small and all digits slender; heel not reaching tympanum; dorsal 



tubercles small, irregular, often arising from a black base; 61 mm. 



hammondii (p. 36) 

 Hand and foot larger, the individual digits thicker; heel usually to tym- 

 panum or as far as anterior edge of eye; dorsal tubercles larger, rounded, 

 and much more numerous; parotoids often very distinct; 65 mm. 

 (composite) multiplicatus (p. 36) 



SCAPHIOPUS COUCHH Baird 



Scaphiopus couchii Baird, Proc. Acad. Nat. Sci. Philadelphia, vol. 7, 1854, p. 

 62.— Kellogg, U. S. Nat. Mus. Bull. 160, 1932, pp. 20-21.— Taylor, Univ. 

 Kansas Sci. Bull., vol. 24, 1936 (1938), p. 508, pi. 44. 



IScaphiopus varians Cope, Proc. Acad. Nat. Sci. Philadelphia, vol. 15, 1863, pp. 

 52-53 (Cape San Lucas, Baja California; type U.S.N. M. No. 5893). 



S{caphiopus] rectifrenis Cope, Proc. Acad. Nat. Sci. Philadelphia, vol. 15, 1863, 

 p. 53 (Tamaulipas; Rfo Nazas, Coahuila; type U.S.N.M. Nos. 3715 [de- 

 stroyed] and 3714). 



Type.—Two cotypes, originally U.S.N.M. Nos. 3713 and 3714, 

 the latter number referred to rectifrenis by Cope. 



Type locality. — Rio Nazas, Coahuila, and Matamoros, Tamaulipas, 

 Mexico. 



Range. — Northern Mexico southward through San Luis Potosi, 

 Nayarit, and Baja Cahfornia. Recorded from the states of Tamauli- 

 pas, Nuevo I<e6n, Coahuila, San Luis Potosi, Chihuahua, Zacatecas, 

 Sonora, Baja California, Nayarit, and Smaloa. 



