MEXICAN TAILLESS AMPHIBIANS 83 



limbs reticulated, marbled, or spotted with brown; distal 

 phalanges of fingers very slightly if at all dilated; first finger 

 as long as or longer than second; fingers not webbed at base; 

 palmar callosities fairly distinct; subarticular tubercles con- 

 tinued backward upon palmar surface; male with two spine- 

 bearing tubercles on inner side of first digit; toes in order of 

 decreasing length, 4, 3, 5, 2, and 1, with vestigial web at base; 

 subarticular tubercles not continued backward upon plantar 

 surface; two metatarsal tubercles, the inner connected with 

 distinct tarsal fold; legs stout; the hind limb being carried 

 forward along the body, the tibio-tarsal joint reaches at least 

 to the tympanum and often to eye; vomerine teeth in two 

 transverse series behind the choanae; tongue small, ovoidal, 

 and slightly notched behind; canthus rostralis indistinct; loreal 

 region oblique; tympanum one-half to two-thirds the diameter 

 of the eye, overhung by a dermal fold; skin of upperparts, 

 sides of body, and upper surfaces of hind limbs with longitu- 

 dinal series of small tubercles; ventral surfaces of thighs 

 granulated; head-and-body length, 35 to 46 mm melanonotus (p. 88) 



LEPTODACTYLUS ALBILABRIS (Gunther) 



1859. Cystignathus albilabris Gunther, Ann. and Mag. Nat. Hist., ser. 3, vol. 4, 



no 21. p. 217. 

 1877. Cystignathus labialis Cope, Proc. Amer. Philos. Soc, vol. 17, no. 100, p. 90, 



July 20 (type locality uncertain, probably Mexico). 

 1877. Cystignathus fragilis Brocchi, Bull. Soc. Philom. Paris, ser. 7, vol. 1, no. 4, 



p. 182 (Tehuantepec, Mexico). 

 1879. C[ystignathus] gracilis Cope, Proc. Amer. Philos. Soc, vol. 18, no. 104, 



pp. 269, 270. June 20. [Nee Cystignathus gracilis Dumeril and Bibbon, 



1841, Erp6tologie g^n^rale, vol. 8, pp. 406, 407 (Montevideo).] 

 1882. Leptodactylus fragilis Brocchi, Mission scientifique au Mexique et dans 



I'Am^rique Centrale, recherches zoologiques, pt. 3, sect. 2, p. 19, pi. 5, figs. 



2-2b. 

 1900. Leptodactylus albilabris GtJXTHER, Biologia Centrali- Americana, Reptilia 



and Batrachia, p. 213, Apr. 



Type locality. — St. Thomas, West Indies. 



Range. — From Cordoba in Vera Cruz south to Tekanto in Yucatan 

 and southward through Central America to Nicaragua; apparently 

 restricted to the State of Oaxaca on the Pacific coast of Mexico. 



Remarks. — The occurrence of this frog on West Indian islands, as 

 well as on the mainland of tropical America, still remains one of the 

 unexplained problems of distributional zoology. Some herpetolo- 

 gists have advocated the recognition of the mainland form as a spe- 

 cies distinct from the one that occurs on a number of the islands. 

 None of the diagnostic criteria thus far suggested will even in the 

 majority of cases serve as a means for the identification of specimens 

 mthout reference to the locality. A reexamination of the types of 

 the species included above in the synonymy and a critical comparison 

 of specimens from the mainland with those from the islands failed to 

 indicate any reliable criteria for such a distinction. 



