68 BULLETIN 194, UNITED STATES NATIONAL MUSEUM 



6. Pupil vertical; first finger opposable to other three; pollex bone forms a 



lateral projection on first finger, but without an exposed spine; 3 



species Agalychnis (p. 71) 



Pupil horizontal 7 



7. First finger with a free rudiment of pollex, and with a free exposed spine; 



2 species Plectrohyla (p. 73) 



First finger without a free rudiment of poUex and without spine 8 



8. A pair of external vocal sacs behind angles of jaws; parotoid spread over 



back; skin thick; 3 species Acrodytes (p. 74) 



No pair of vocal sacs behind jaw angles; parotoids absent or indistinct. _ 9 



9. A pair of subgular vocal sacs in males; 1 species Srailisca (p. 75) 



None or a single subgular vocal sac 10 



10. No large ventrolateral gland present; individual horny nuptial rugosities 



on first finger of male, small or absent 11 



A large ventrolateral gland present; nuptial rugosities on male, relatively 

 very large, and reduced in area and numbers; 1 species. Ptychohyla (p. 91) 



11. Vomerine teeth absent; vocal sac present or absent; a broad fold of skin 



along side to groin; head wide and flat; 2 species Hylella (p. 76) 



Vomerine teeth present (absent in H. picta, in which case there is no 

 lateral fold of skin) 12 



12. Tips of digits not dUated; small terrestrial forms; 1 species Acris (p. 77) 



Tips of digits widened; arboreal and terrestrial forms; 37 species. Hyla (p. 77) 



Genus CENTROLENELLA Noble 



Centrolenella Noble, Bull. Amer. Mus. Nat. Hist., vol. 42, 1920, p. 441. 



Genotype. — Centrolenella antioquiensis Noble. 



Range. — Guerrero to Ecuador. 



Species. — Five, of which two occur in Mexico.'" 



KEY TO MEXICAN SPECIES OF CENTROLENELLA 



1. Tibiotarsal articulation reaching several millimeters beyond tip of snout; 

 upperparts smooth; head broad; no fleshy folds on thighs near anus; 

 iris of eye, golden; choanae very large; a cream spot on eyelid; heels 

 overlapping when legs are folded at right angles; 24 mm. 



fleischmanni (p. 68) 

 Dorsal surface of body and limbs covered with minute rugosities; forearm 

 and toes distinctly broader than preceding, and hand larger; body 

 somewhat shorter and thicker proportionally; iris of eye dark black; 

 heel reaches nostril; no cream spot on eyelid; heels barely touching 

 when legs are folded at right angles to body; maximum size, 23 mm. 



viridissima (p. 69) 



CENTROLENELLA FLEISCHMANNI (Boettgcr) 



Hylella fleischmanni Boettger, Bericht. Senck. Nat. Ges., 1893, p. 251. 

 Centrolenella fleischmanni Noble, Proc. Biol. Soc. Washington, vol. 37, 1925, 

 pp. 66, 69.— Taylor, Univ. Kansas Sci. Bull., vol. 28, 1942, p. 74. 



M Some authors combine these with Centrolene Jlmfinez de la Espada, 1872 (Anal. Soc. Esp. Hist. Nat. 

 vol. 1, p. 87; type C. geekoideum Jimfinez de la Espada, Rio Napo, Ecuador), comprised of three species with 

 humeral books in males and sometimes in females. 



