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FROGS AND TOADS. 
ened and furnished with horny sheaths. In some of the genera, and especially the 
one of which a representative is here figured, the mouth is extremely narrow ; 
and although it is convenient to take this character as the basis of the name of the 
family, it must not be considered that it is applicable to all its members. These 
narrow-mouthed forms feed exclusively or mainly on ants and termites, and thus 
exhibit a modification of structure approximating to that characteristic of ant- 
eating mammals. More than half the members of the family are nocturnal, and 
may be recognised by the vertical pupil of the eye. 
Short-Headed The exceeding plumpness of the body serves not only to dis- 
Frogs. tinguish the short-headed frogs ( Breviceps ) from all their allies, but 
also makes them some of the most peculiar of their class. Indeed, when the body 
EAST AFRICAN SHORT-HEADED FROGS (liat. size). 
is puffed out to its fullest extent, they more resemble indiarubber balls than frogs. 
The genus belongs to a group in which the so-called precoracoid bones are present 
and the metacoracoids much dilated; and they are specially distinguished by the 
horizontal portion of the pupil and the absence of teeth on the palate. Three 
species are known, all of which are African, the one here figured ( B. mossambicus) 
inhabiting the eastern districts. Generally having a perfectly smooth skin, this 
frog is of a brown or blackish hue on the upper-parts, with a dark oblique streak 
below the eye. The narrow mouth and long tongue of this curious frog indicate 
that its food consists of white ants. 
Darwin's Frog. 
A frog (Rhinoderma danvini ) belonging to the present family, 
and inhabiting Chili, alone represents a genus remarkable for the 
