9. HYLODEs. 211 
are abruptly incurved without meeting ; tympanum distinct, a broad 
vertical oval, as large as the eye. Disks and subarticular tubercles 
of fingers and toes small. The hind limb being carried forwards 
along the body, the tibio-tarsal articulation reaches the eye. Skin 
smooth; two suprascapular longitudinal dermal folds, converging 
towards the middle line without meeting. General colour ashen 
grey; a large black spot below the eye, and another above and on 
the tympanum ; a dark band with a pale superior border above each 
ilium ; belly and concealed faces of hind limbs yellow, coarsely 
reticulated with blackish ; throat thickly dusted with the same. 
W. coast of Central America. 
22. Hylodes megacephalus. 
Lithodytes megacephalus, Cope, Journ. Ac, Philad. (u. s.) vill. 1876, 
p. 110, pl. 23. f. 11. 
Tongue oval, entire. Vomerine teeth in two short approximated 
series entirely behind the choane. Head very large, broader than 
the body ; canthus rostralis distinct; nostril nearer the tip of the 
snout than the eye; orbits oblique, the superciliary borders rising 
from the end of their anterior third into a strong ridge, which runs 
in a straight line and terminates abruptly in a slight thickening at 
the posterior border of the cranium; posterior half of the cranium 
above deeply grooved; tympanum distinct, vertically oval, one third 
the diameter of the eye. Limbs short. Toes entirely free ; disks of 
fingers and toes small; a single metatarsal tubercle. Skin smooth 
above and beneath, with the following exceptions :—A dermal fold 
extends from each exoccipital region on each side of the back, pur- 
suing a concave course to the middle of the transverse process of the 
sacrum ; a similar fold extends from the vent on each side, in an 
oblique direction, to the end of the transverse sacral process ; sides 
of body areolated. Light ash above; a black spot extends from the 
tympanum to the scapula, and sends a line to the eye; limbs cross- 
barred ; hinder side of thighs black, marbled distally with ash; sole 
of foot black ; lower surfaces white, marbled with black. 
Pico Blanco, Costa Rica. 
23. Hylodes gulosus. 
Lithodytes gulosus, Cope, J. c. p. 112. 
Very closely allied to H. megacephalus, from which it differs in the 
following points :—Head relatively smaller. No dermal plice. 
Dark leather-brown above; a black spot across the tympanum, and 
one under the eye ; brown beneath, irregularly marbled with white. 
Size of Leptodactylus pentadactylus. 
Pico Blanco, Costa Rica. 
P2 
