9. HYLOBBS. 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 yeJlow, coarsely 

 reticulated with blackish ; throat thickly dusted with the same. 

 W. coast of Central America. 



22. Hylodes megacephalns. 



Lithodytes megaoephalus, Cope, Journ. Ac. PhUad. (n. s.) viii. 1876, 

 p. 110, pi. 23. f. 11. • 



Tongue oval, entire. Vomerine teeth in two short approximated 

 series entirely behind the choanse. 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 j lower surfaces white, marbled with black. 



Pico Blanco, Costa Eica. 



23. Hylodes gulosus. 



Lithodytes gulosus, Cope, I. c. p. 112. 



Very closely allied to H. megaeephalus, from which it differs in the 

 following points : — Head relatively smaller. No dermal plicae. 

 Dark leather-brown above ; a black spot across the tympanum, and 

 one under the eye ; brown beneath, irregularly marbled with white. 

 Size of Leptodactylus pentadaotylus. 



Pico Blanco, Costa Rica. 



p2 



