TREE-FROGS. 



279 



the webbing of the hind-toes ; while there is a fold on the ankle, and the tubercles 

 on the joints of the lower surface of the hind-toes are to a large extent double. 

 The hind-limb is unusually short ; the flattened warts on the back are distinctly 

 porous; the glands behind the eyes are small, depressed, and either oval or 

 triangular; and there is an additional gland on the leg. The general colour of 

 the upper-parts is light olive, with darker marblings or spots, the above-mentioned 

 light line being generally present; while the light under-parts are more or less 

 spotted with black. In its movements the natterjack is less sluggish than the 

 common toad, its pace being often quickened to a kind of run, during which the 

 body is raised considerably above the ground. It is likewise less intolerant of 

 drought, being frequently found in hot, sunny situations, and only resorting to the 

 neighbourhood of water during the breeding-season. 



Sharp-Nosed The Mexican sharp-nosed toad (Rhinophrynus dorsalis), already 



Toad. referred to as subsisting on white ants, is the only other member of 

 the family that we have space to mention, and is generically distinguished by the 

 long and narrow tongue being free in front, by the vertical pupil of the eye, and by 

 the rudimentary breast-bone. The front-toes are free, and those of the hind-limb 

 webbed, with simple tips ; while the general form of the body is extremely stout ; 

 the head small, with a long, truncated muzzle and narrow mouth ; the eyes being 

 small, and the limbs remarkably short. In colour this toad is olive-brown or 

 bluish grey above, frequently with yellowish spots on the flanks and middle of 

 the back, those on the back sometimes uniting to form a line. 



THE OVEELAPPING-CHESTED TKEE-FROGS. 

 Family HYLID^E. 



The numerous, mostly arboreal, frogs thus designated form a family compris- 

 ing some ten genera, very abundant in Australia and America, and more sparingly 

 represented in Europe, Asia north of the Himalaya (one species ranging into North- 

 Eastern India and Burma), and 

 Northern Africa. While resem- 

 bling the toads in the expansion 

 of the processes of the sacral 

 vertebra, they differ by the pre- 

 sence of teeth in the upper jaw, 

 and they are peculiar in the claw- 

 like form of the terminal joints 

 of the toes. The vertebrae are 

 cupped in front, and spherical 

 behind, and there are no ribs. 

 Grasshopper- The grass- 



hopper- frog (Acris 

 gryllus)oi North America is the 

 sole representative of a genus 

 characterised by the horizontal 

 pupil of the eye, the webbing of 



GRASSHOPPER-FROGS '(nat. size). 



