SOUTHERN FROGS. 
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there is never any expansion of these extremities. The outer metatarsals are 
completely united, and the skull is remarkable for the extent to which ossifica¬ 
tion is carried out. In some species, such as the Brazilian horned frog ( 0. boiei), 
the upper eyelid is produced into a horn-like appendage; but in others, like the 
Argentine horned frog ( Gornata), this is little developed and scarcely noticeable. 
The largest representative of the genus is the above-mentioned Brazilian 
horned frog, which attains as much as 8 inches in length, and is one of the most 
handsomely ornamented of the genus. The smaller Argentine species represented 
in our illustration differs from it by the upper eyelid being only slightly 
pointed and triangular, as well as by the presence of a bony shield on the back. 
The skin is covered with tubercles above and granules below; the general colour of 
the upper-parts being yellowish or greenish, with large olive spots surrounded by 
light-coloured or golden margins, while there are sometimes wine-red lines between 
the spots. These frogs, or escuerzos, as they are locally called, are abundant in 
many parts of Argentina, and in damp weather may be met with crawling about 
among the grass in numbers, after the manner of toads. They are exceedingly bold 
and ferocious, flying fiercely at anyone who attacks them, and maintaining their 
hold with the tenacity of a bull-dog, at the same time uttering a kind of barking 
cry. On other occasions they give vent to a peculiarly deep bell-like note. When 
in repose, escuerzos are in the habit of burying themselves in the soil with only the 
top of the back exposed, in which state they are almost invisible. In this position 
they lie in wait for their prey, which includes other frogs, birds, and small mammals; 
and at times they capture and attempt to swallow objects too large for their capacity. 
ARGENTINE HORNED FROGS, OR ESCUERZOS (liat. size). 
