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 Overlapping-Chested Tree-Frogs. 
Family II YLIDJE. 
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- 
Fr °£- 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). ' 
