THE BATftACHlA OF NORTH AMERICA. 297 



I. Cavum tympani and tyuipaiium wauting. Xiphisternum with an ossiQed proxi- 

 mal style. Cimeiform boue and sbeath well developed. Pupil erect. Toes 

 webbed. 

 Derm involved in cranial ossification. Temi)oral fossa with a strong roof. 



Vomerine teeth : no parotoid glands CuJtv'ipes. 



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

 otoid glands. Vomer! no teeth Pelohufes. 



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

 parietal bars inclosing a median fontanelle. Vomerine teeth. No paro- 



toids Didociis. 



Cuneiform bone aud sheath well developed. Toes more or less webbed. 

 II. Cavum tympani aud tympanum present. Xiphisternum entirely cartilaginous. 

 Pupil elliptic erect. 

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



and vomerine teeth Seaph iopiis. 



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

 superciliary bars. Parotoid glands and vomerine teeth Spea. 



The extreme of divergence of the series of this famil^^ is, then, that 

 representing^- its type in a pre eminent degree. This is seen in the genus 

 Cultripes where the ossification of the superior cranial walls is espe- 

 cially thickened, obliterates the sagittal suture, and is extended in an 

 arch over the temporal fossa. The anterior ossification of the coccyx is 

 applied by its axial portion beneath the axis or centrum of -the sacral 

 vertebra, and becomes consolidated with it shortly after its commence- 

 ment, furnishing a structure not rare among burrowing Anura. This 

 character is maintained in the descending scale b}' Pelobates, Didocu.s, 

 Scaphiopus, and Spea, though none of these have the temporal fossa 

 overarched. Cultripes, with Pelobates and Didocus, exhibit an ossified 

 basal xiphisternal piece, while in all below it is cartilaginous, as in most 

 Arcifera; the extreme position of the former is also maintained by the 

 obliteration of many portions of the auditory apparatus. The succeed- 

 ing forms — Scaphiopus and Spea — resemble the first group in the toad- 

 like form and in the strong cuneiform shovel and webbed feet. 



The distribution of the si)ecies of the family is as follows : 





K. Neotrop. 



E. Nearctica. 



R. Palicarct. 



Cultripes.- 





 

 

 

 





 

 

 2 

 2 



0)1 

 1 







1 



Scaphiopus 







Spea 

















4 



3 



The inferior dermal attachments of seven species of this family are as 

 follows : 



Didocus calcaraltis. Belly more than half attached. 



Felohates fuscus. From half to two- thirds attached ; same in larva, with long tail ; fe- 

 mur one line below. 



ScapJiiopus holbrookii. Free only opposite sternum ; thigh attached only below on 

 basal half. 



Scaphiopus couchii. Triangular free area to middle abdomen. 



