The shape of the body is generally very stout. The limbs are short, notably so in _Glyphoglossus_, _Breviceps_, _Rhombophryne_, _Hemisus_, _Stereocyclops_ and _Cacopus_. Others, for instance most species of _Microhyla_, _Phryniscus_, _Callula_, and _Sphenophryne_, are of a very slender build; and their limbs, instead of being short and well adapted to digging, are long and may even be provided with typical adhesive discs, supported by T-shaped phalanges, especially in the two genera last named, and in _Scaphiophryne_ and _Phrynomantis_. However, none of the forms provided with discs are known to be arboreal. Exceptional diversity is shown in the shoulder-girdle and sternum. The omosternum occurs only in _Rhinoderma_ and _Hemisus_. The metasternum is a cartilaginous plate, very large in _Cacopus_, distinctly small in _Breviceps_, and almost absent in _Hemisus_. The precoracoids and clavicles show all stages from a well-developed condition (_Breviceps_, _Rhombophryne_, _Hemisus_, _Rhinoderma_, _Phryniscus_ and _Brachycephalus_) to complete absence. The circumstance that these bars are very weak in _Melanobatrachus_, _Calophrynus_, _Scaphiophryne_ and _Hypopachus_, i.e. in Palæo- and Neo-tropical genera, indicates a widespread tendency towards complete suppression, a feature independently aimed at both in America (_Engystoma_) and in the Old World. Until we know something about the habits of the members of this much diversified sub-family, it is idle to connect the various modifications with each other, and thus, by correlation, to find out their meaning. Those forms which possess well-developed discs on their fingers and toes are said not to be arboreal. What is the true meaning of the prominent snout which is not restricted to the digging forms? Most of the good diggers have well-developed precoracoid bars, and the coracoids are distinctly strengthened, but in _Glyphoglossus_ and in _Cacopus_ the precoracoids are entirely {227}absent, and this loss is compensated for by exceptionally strong coracoids. On the whole, those genera are to be considered as the most primitive which have undergone the fewest losses. Those with a complete shoulder-girdle, with an omo- and meta-sternum and with simple phalanges, are necessarily the older forms. One step farther back in another direction, the possession of teeth on the palate, and on the upper jaw, leads to those genera which have been separated off as DYSCOPHINAE, while teeth in the lower jaw constitute the GENYOPHRYNINAE. Lastly, the firmisternal type has necessarily been evolved from the arciferous condition, and there the two Bufonid genera _Myobatrachus_ and _Rhinophrynus_, the former Australian, the latter Mexican, with their narrow and scarcely overlapping epicoracoid cartilages, seem to form a connecting link, although their ant-eating habits, with concomitant modifications in structure, may be nothing but cases of convergent evolution. Key to the genera:–