THE TOAD FROGS 2649 



On account of the peculiarity of their reproduction, mention must 

 be made of the curious pouched tree frogs (Nototrema), distinguished 

 from the typical genus by the presence of a backwardly-opening pouch 

 at the hinder end of the back in the females. These frogs are represented by some 

 half-dozen species, mainly confined to Central and Western tropical America, al- 

 though one of their number is found on the eastern side of that continent at Per- 

 nambuco. The pouch of the female is extended beneath the skin of the back and 

 sides to form a very large chamber, in which the eggs and tadpoles undergo the 

 whole of their transformations. The eggs, generally fifteen or sixteen in number, 

 appear to be placed in the pouch by the male, who employs his hind-feet for the 

 purpose; and they are remarkable for the large relative size of the yolk. The tad- 

 poles, when first hatched, are peculiar in having a bell-shaped structure for the 

 protection of their two pairs of external gills. 



THE TOAD FROGS 



Family 



The fifth family of the order belonging to the section with overlapping carti- 

 lages to the metacoracoids comprises eight genera, which may be collectively termed 

 toad frogs, since they come neither under the designation of toads or frogs. 

 Agreeing with the tree frogs in the presence of teeth in the upper jaw, they may be 

 distinguished by the much greater expansion of the processes of the sacral vertebra, 

 ribs being absent, and the terminal joints of the toes simple. In all the forms the 

 pupil of the eye is vertical; and whereas the majority of the genera agree with the 

 preceding groups in having the articular cup at the front and the ball behind, in a 

 few this arrangement is reversed. The family is distributed over Europe, the 

 Oriental region, North America, and New Guinea; the various genera having a 

 more or less restricted geographical range. 



The brown toad frog (Pelobates fuscus) is the typical representative 

 _ of a genus containing two European species, neither of which are 

 found in Britain. They are characterized by the rod at the end of the 

 backbone being welded to the sacral vertebra, and by the extensive webbing of the 

 hind- toes; the presence of a bony style to the breastbone, coupled with the want of 

 an externally visible ear membrane, serving to distinguish them from an allied 

 North- American genus {Scaphioptis} . The brown toad frog is a rather large 

 species, usually measuring from two and one-half to three inches in length, and 

 having a smooth brown skin, marbled on the upper parts with darker markings; a 

 spur which is present on the metatarsus being yellowish brown. The males have 

 no vocal sac, but are furnished with a large elliptical gland on the upper surface of 

 the fore-limb. This species is decidedly local, and in some districts is replaced by 

 the allied P. caltripes, easily distinguished by the black spur on the metatarsus. 

 Spending only a few days during the breeding season in the water, it is essentially 

 a land animal, generally frequenting spots with a sandy soil. Here, with the aid of 



