GENERA OF THE ARCIFEROUS ANURA. 81 



articulation, its axial portion restricting that of the sacrum and connate with it : 

 external metatarsi bound ; distal phalange continuous, simple. Manubrium carti- 

 laginous. Tongue rounded, nearly entire. 



The small number of species embraced in this family are of stout toad-like 

 habit, and furnished with a shovel-like development of the cuneiform bone and a 

 coriaceous posterior digital palmation, to aid them in removing earth while making 

 their subterranean al^odes. Manj' of them very seldom come to tlie surfece of the 

 earth, and then only in darkness; for this habit the vertical cat-like pupil is an 

 adaptation, a peculiarity not exhibited by the toads, which are crepuscular. 



Group I. Cavum tympani and tympanum wanting. Xiphisternum with an ossified 

 proximal style. Cuneiform bone and sheath well developed. Pupil erect. 

 Toes webbed. 

 Derm involved in cranial ossification. Temporal fossa with a strong roof 



Vomerine teeth : no parotoid glands, ...... Cultripes. 



Derm involved in cranial ossification. No roof over the temporal fossa, 



or parotoid glands. Vomerine teeth, ...... Pelobates. 



Derm distinct from cranium, which is undeveloped above, two lateral 

 fronto-parietal bars enclosing a median fontanelle. Vomerine teeth. 

 No parotoids. .......... Didocus.* 



Group II. Cavum tympani and tympanum present. Xiphisternum en- 

 tirely cartilaginous. Cuneiform bone and sheath well developed. 

 Toes more or less webbed. Pupil elliptic erect. 

 Derm involved in the cephalic ossification, which is complete. Parotoid 



glands and vomerine teeth, ........ Scaphiopus. 



Derm distinct from cranium, which is only ossified superiorly in two 



superciliary bars. Parotoid glands and vomerine teeth, . . . SpEA.f 

 The extreme of divergence of the series of this family is, then, that representing its 

 type in a preeminent degree. This is seen in the genus Cultripes where the ossifica- 

 tion of the superior cranial walls is especially thickened, obliterates the sagittal 



* Type Rana calcarata Michahelles Isis von Oken, 1830, 160. In the lack of a good series of specimens 

 of Cultripes provincialis, I should have hesitated to separate this species generically from the latter, re- 

 membering the very late period of completion of the cranium in Ranoidea a u r e a of Australia. But Dnges' 

 " Rech. Ost. et Myol.," etc., p. 03, says that the parasphenoid and frontoparietal bones are simultaneously 

 and early completed, and illustrates in a figure the confluence of the latter while quite youug. Dumeril, 

 Brp. Generale, viii. 484, states, moreover, that the temporal roof is developed before the tail of the larva has 

 disappeared. In our specimen, which is fully developed, though not of large size, the temporal muscles 

 are only enclosed by the usual fascia. The species occurs in southern Spain. See my forthcoming memoir 

 in the Smithsonian Contributions. 



t Type Scaphiupus bomhifrons Cope: embraces S. hammondii Baird. and S. m u 1 1 ipl i c a t u s 



Cope. 



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