2638 FROGS AND TOADS 



real forms, the family comprises terrestrial, aquatic, and burrowing representatives; 

 the last having either the front- or hind-limbs specially strengthened and furnished 

 with horny sheaths. In some of the genera, and especially the one of which a rep- 

 resentative is here figured, the mouth is extremely narrow; and although it is con- 

 venient to take this characteristic 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 modifica- 

 tion of structure approximating to that characteristic of ant-eating mammals. More 

 than half the members of the family are nocturnal, and may be recognized by the 

 vertical pupil of the eye. 



The exceeding plumpness of the body serves not only to distinguish 



the short- headed frogs (Brevicebs} from all their allies, but also makes 

 Frogs 



them some of the most peculiar of their class. Indeed, when the body 



is puffed out to its fullest extent, they more resemble India-rubber 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 spe- 

 cies are known, all of which are African, the one here figured (Z?. mossambiats) in- 

 habiting 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. 



A frog (Rhinoderma darwini] belonging to the present family, and 

 g inhabiting Chili, alone represents a genus remarkable for the throat 

 sac of the males being enlarged and modified so as to form an extensive chamber 

 on the under surface of the body in which the eggs and tadpoles undergo their 

 development. This chamber is entered by two apertures situated on the floor 

 of the mouth on each side of the tongue; and when the eggs, generally from 

 eleven to fifteen in number, are laid by the female, they are taken and swallowed 

 by her consort, who passes them into his pouch. When the tadpoles are suffi- 

 ciently developed, they enter the world by escaping through the parental mouth. 

 It appears that at no stage of their existence do the tadpoles possess external 

 gills. 



THE SHARP-NOSED FROG 



Family CERA TOBA TRA CHfDsE 



Omitting detailed mention of the small and unimportant family of the Disco- 

 phidce, characterized by the presence of teeth in the upper jaw, and the expansion 

 of the extremities of the transverse processes of the sacral vertebra, our last repre- 

 sentative of the first suborder is the sharp-nosed frog (Ceratobatrachus guentheri), of 

 the Solomon islands, which constitutes a family by itself. The essential character- 

 istics of the family are the presence of teeth in both the upper and lower jaws (a fea- 

 ture found elsewhere only in two families of the next suborder), coupled with the 



