284 FROGS AND TOADS. 



months these have completed their development and leave the water. When an 

 adult toad-frog is suddenly seized or pinched, it utters a cry like the mewing of a 

 kitten, at the same time emitting a pungent vapour with a strong odour of garlic, 

 both these being apparently intended as a means of defence. 



Of the remaining genera, Pelodytes, as represented by the 

 punctured toad - frog (P. punctatus) of Western Europe, and the 

 Papuan Batrachopsis, differ from the preceding in that the sacral vertebra 

 has two condyles for articulation with the rod forming the termination of the back- 

 bone, the hind-toes being slightly webbed. In the Oriental genus Leptobrachium, 

 there is but a single condyle for the articulation of the rod-like bone. 



Allied In the Miocene rocks of Europe there occur remains of numerous 



Extinct Frogs, frogs which are assigned to an extinct genus, Palceobatrachus, regarded 

 as representing a family (Palceobatrachidce) connecting the present one with the 

 under-mentioned Xenopodidce. In these extinct forms the upper jaw is toothed, 

 the transverse processes of the sacral vertebra have expanded extremities ; the 

 sacral vertebra articulates with the terminal rod of the backbone by means of two 

 condyles ; the vertebrae have their articular cup in front ; and there are no ribs. 



THE Disc-ToNGUED FROGS. 

 Family DlSCOGLOSSlD^l. 



The disc-tongued frogs, as the members of this group may be called, form a 

 small family represented by four genera and seven species, inhabiting the northern 

 half of the Old World and New Zealand. As a family, these frogs are characterised 

 by the presence of teeth in the upper jaw, the expansion of the processes of the 

 sacral vertebra, the presence of short rudimentary ribs, and the circumstance that 

 in the bodies of the vertebrae the articular cup is placed at the hinder-end, and the 

 ball in front. In both the latter respects these frogs resemble the salamanders and 

 newts, and they may accordingly be regarded as some of the least specialised repre- 

 sentatives of the order. Their remains occur abundantly in the middle Tertiary 

 rocks of Europe. The family derives its name from the disc-like form of the 

 tongue, which may be either free or adherent. From all the forms hitherto described, 

 the tadpoles, after shedding the external gills, differ in having the breathing-pore 

 situated in the middle of the under surface of the body, instead of on the left side. 

 Fire-Bellied From the painted frog (Discoglossus pictus) of Southern Europe 



Fr - and North- Western Africa, which alone represents the typical genus 

 of the family, the fire -bellied frog (Bombinator igneus), represented in the 

 figure on p. 257, is distinguished by the absence of an external tympanic mem- 

 brane to the -ear ; while it is further characterised by the adherent tongue, the 

 triangular form of the pupil of the eye, and the great expansion of the extremities 

 of the transverse processes of the sacral vertebra. This frog, which inhabits 

 Europe and Asia, although unknown in the British Islands, has the skin very warty 

 on the upper-parts, while beneath it is nearly smooth. In colour it is olive above, 

 with or without black marblings ; while beneath it is orange or yellow, marbled 

 with black. The males are devoid of a vocal sac, but during the breeding-season 



