vi ENGYSTOMATINAE DYSCOPHINAE 235 



a deep guttural croak, ' wau-auhhhh,' very strident and prolonged. 

 The males croak while floating on the surface of the water, the 

 single vocal sac under the mouth inflated like a globe, and the 

 anus and legs extended. They can hop well on land and are good 

 swimmers. The skin is excessively slimy ; the secretion comes off 

 profusely, and dries on the hand into a sort of white gum, with 

 a faint aromatic smell. This gum dissolves in hot water and 

 coagulates in cold. The general appearance of these frogs is very 

 stout, their girth being about twice the length from snout to 

 vent. The tongue, which is oblong in spirit specimens, in life is 

 very elastic, assuming, when extended, a vermiform shape and 

 reaching about 4 cm. in length. They appear after sunset, 

 crawling on old wood and feeding on white ants." 



Sub-Fam. 2. Dyscophinae. -With teeth in the upper j>': 

 This small group of nine genera, with scarcely more than one 

 dozen species, all with one exception living in Madagascar, has 

 been separated by Boulenger from the Engystomatinae merely on 

 account of the presence of teeth on the upper jaw and on the 

 vomerine margin of the palatine bones. He himself remarks that 

 Calluella may be considered a toothed Hypopachus, and Pletho- 

 dontoliyla a toothed Callula. These are obvious cases of con- 

 vergent analogy. Except for the teeth, the Indian Calluella 

 would be merged into the American Hypopachus, and this would 

 present an instance of the most puzzling geographical distribution. 

 In the case of the other two genera, one Indian and Malayan, the 

 other Malagasy, no such suspicion would arise, since there are 

 many other instances of such a coincidence of distribution. There 

 is the same divergence or unsettled condition in the modification 

 of various parts in the Dyscophinae as in the Engystomatinae. 

 The precoracoid bars are weak and curved backwards, and closely 

 pressed against the strong coracoids, in Dyscophus, Calluella and 

 Platypelis, while these elements are reduced to unossified bars, 

 and the clavicular portions completely lost, in Plethodontohyla 

 and in Phrynocara. The omosternum is absent and the meta- 

 sternum is small in all except Dyscophus, in which both these 

 parts are exceptionally well developed and large, although re- 

 maining unossified. The palate of Dyscophus and Calluelt" is 

 provided with curious, serrated dermal folds like those which are 

 so common in the Engystomatinae ; and well-developed discs on 

 the fingers and toes, supported by T-shaped phalanges, are 



