HYLIDAE 



185 



Rhinophrynus dorsalis of Mexico is remarkable for its tongue, 

 which is elongated, subtriangular and free in front, so that it 

 can be protruded directly — not by reversion as in other toads 

 — and can be used for licking up the termites which seem to be 

 its principal food. The body of this ugly creature is almost egg- 

 shaped, and the head is merged into this mass, only the narrow 

 truncated snout protruding. The limbs are very short and stout. 

 The toes are more than half webbed, and there is a large oval, 

 shovel-like metatarsal tubercle, covered with horn and used for 

 digging. The general colour is brown, with a yellow stripe 

 along the spine and with irregular spots and patches on the 

 flanks and limbs. Total length 2 to 2^ inches. 



Fam. 4. Hylidae (Tree-frogs). — The upper jaw — in Am2}hi- 



FiG. 36. — Map showing distribution of Hylidae. The vertically shaded countries are 

 inhabited by Ilyla and by other genera of Hylidae ; the horizontally shaded countries 

 only by llyla. 



gnathodon the lower jaw also — and the vomers carry teeth; 

 Triprion and Diaglena alone have teeth on the parasphenoid also, 

 and the latter genus is further distinguished by possessing 

 palatine teeth. The vertebrae are procoelous and have no ribs ; 

 the sacral diapophyses are dilated. The omo- and meta-sternum 

 are cartilaginous, the latter forming a plate with scarcely any 

 basal or style-shaped constriction. The terminal phalanges are 

 invariably claw-shaped and swollen at the base, and carry a 

 flattened, roundish, adhesive cushion. The tympanic disc is 

 variable in appearance, being either free, or more or less hidden 

 by the skin. The tongue is also variable in its shape and in the 

 extent to which it can be protruded. 



