VI ENGYSTOMATINAE 2 2/ 



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 siniy)le plialanges, 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 tliere the 

 two Bufouid genera Myohatrachvs 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 moditications 

 in structure, may be nothing but cases of convergent evolution. 



Key to the genera : — 



I. American. .4. with (nnosternuni .... Rhinoderma, p. -228. 



B. witlioiit omosternuni. 

 'I. Pupil horizontal. 



Precoracoids jiresent. 



Sacrals strongly dilated. Orcophrijnella. 

 „ moderately „ . Phryniscus, p. 230. 

 ,, feebly „ . Brachycephalus, j). 231. 



b. Pupil vertical. 



a. Precoracoids feeble. . Hypopachus. 



f3. „ absent. . Engystoma, p. 231. 



c. Pupil iinmd. Precoracoids 



jtresent . . . Stercocyclop.s, p. 231. 



II. Palaeotrojiical. a. Puj^il horizontal. 



(t. Precoi'acoids jiresent. 



With palatal teeth. ^Madagascar. 



Rhomhojyhryne. 

 Palate with dermal ])a])illae. Africa. 



Breviceps, \\ 232. 

 With palatal dciiiial i'old.s. Madagascar. 



Scaphio2}hryne. 

 \\"\\]\ sexTated palatal folds. Madagascar and 



India. Calo2)hryn us. 

 Palali' smooth. New Guinea. Sj)henophryne 



and Liophryne. 

 (i. Prccoi'ac(;ids al)sent. 



Malacca. . . Phrynella, \>. 233. 



New Guinea . Mantophryne. 



Africa .... Cacosteriuim. 



