436 AMPHIBIA ORDER L-ECAUDATA. 



first ten of these families are divided into two larger groups are taken from the 

 skeleton, and are consequently some what difficult to explain to readers not speci- 

 ally versed in anatomy. 



Sub-Order J. Firmisternia. 



The five families constituting this subordinal group are characterised as 

 follows : The tongue is present, and the large plate-like bones on the chest 

 termed the metacoracoids are united together by a large median cartilage, 

 attached to their free inner margins. 



in the family typified by the common British frog teeth are developed in 



the upper jaw, and the horizontal transverse processes of the sacral vertebra 



have, at most, only a slight terminal expansion, and are fre- 



Typical Frogs. quently cylindrical throughout. The frogs of this family 



Family Ranidce. display remarkable diversity in the form of the tips of the 

 terminal bones of the toes, which may be either rounded, 

 pointed, forked, T-shaped, or, more rarely, claw-like. The family which 

 includes a large number of genera and a host of species has a wide geo- 

 graphical distribution. With the 

 exception of a species of the typical 

 genus from the extreme north of 

 Australia, and another belonging to 

 the genus Cornifer from New 

 Guinea, there are no members of 

 the family in Australasia. South 

 America, too, is poorly off, having, 

 in addition to certain species be- 

 longing to the typical genus .Roma, 

 only live genera, and about a dozen 

 species. Moreover, since none of 

 these latter range farther south than 

 Ecuador and Colombia, while Rana 



.-COMMON FROG (Rana temporaria). does nofc apparent i y extend south- 

 ward of Amazonia, the more southern 



parts of that continent aro characterised by the total absence of the present 

 family. In a group so extensive, it is difficult to select genera for special 

 notice, although the typical Ratia must of course be mentioned. In the 

 numerous irogs of this genus the tongue is free and more or less deeply 

 notched at the tip, the pupil of the eye forms a horizontal slit, and the toes 

 of the fore-feet are free, whereas those of the hind-feet are more or less fully 

 webbed. By putting the finger into the mouth of any frog of this genus, it 

 will be readily felt that teeth are present on the vomers, occupying the 

 middle region of the palate. Whereas in some forms the tips of the toes are 

 simple, in others they are dilated. The genus has a distribution nearly 

 coextensive with that of the family, one species being found in the extreme 

 north of Australia, although there is none from Papua. There are several 

 species of the genus inhabiting Europe, such at> the common frog (R. tetn- 

 poraria), the edible frog (R. esculenta\ the agile frog (R. agilis), the Spanish 

 frog (R. iberica), and Lataste's frog (R. Icttastei). Of these, the only one 

 indigenous to Britain is the common frog, in which the hind feet are incom- 

 pletely webbed, and the males are unprovided with the dilatable throat -sacs 

 characterising those of the edible species. Although the latter of which 



