HYLA.—HYLELLA. 285 
side; a cross-fold above the vent; a short cutaneous appendage at the heel. The 
rudimentary pollex scarcely projects beyond the skin. Abdomen granular, throat and 
chest smooth. Fold across the chest incomplete. Yellowish or pinkish, uniform or 
minutely speckled with purple or with some irregular white spots; concealed parts of 
the thighs not coloured. Lower parts whitish. The fold over the vent and the edge 
of the hind foot from the heel milky-white. Male with a subgular vocal sac. 
Brazil. Costa Rica. 
Greatest width ofhead . . . . . . . . 19 millim. 16 millim. 
Distance of vent from snout. . . . . . . 51. ,, 46s, 
» ” heel . . . . «OBS, 48, 
- - metatarsal joint . . . 68 ,, 64 a, 
» 7 end of fourth toe. . . 89 _,, 81 sa, 
The single Central-American specimen which I have examined differs from those of 
Brazil and Guiana in having the lateral fold of the skin only indicated for a very short 
distance, scarcely extending beyond the tympanum. 
38. Hyla rudis, 
Alyla rudis, Mocquard, Bull. Soc. Philom. (9) i. p. 163, t. 1. fig. 8 (1899). 
Hab. Mexico, Guadalajara (Diguet). 
The skin is adherent to the bone and rough on the upper surface of the head and in 
the loreal region. 
Vomerine teeth in two small groups, between the choane. Head depressed, broader 
than long; snout conspicuously longer than the eye, with rugose canthus ; distance of 
the nostril from the eye equal to the diameter of the latter, which is twice the length 
of the tympanum. Interorbital space much broader than the supraocular cover. 
Fingers free, toes one-third webbed ; disks smaller than tympanum. No tarsal fold. 
When carried forward, the heel reaches the eye. Upper parts finely granulated; a 
fold above the tympanum and across the thorax. Brownish-olive, with some darker 
spots; lower parts whitish. (After Mocquard.) 
Length of body . . . . . . . . . 85 millim. 
HYLELLA. 
Aylella, Reinh. & Liitk. Vidensk. Meddel. 1861, p. 199; Bouleng. Batr. Sal. p. 419. 
Exerodonia, Brocchi, Bull. Soc. Philom. (7) ii. p. 19 (1879). 
Pupil horizontal. Tongue entire or but slightly emarginate behind. Vomerine 
teeth none. Fingers and toes dilated into terminal disks, the latter always webbed. 
Auditory organ developed; tympanum present or hidden under the skin. Outer 
metatarsals united. 
BIOL. CENTR.-AMER., Batr., September 1901. *93 
37 
