104 ON THE STRUCTURES AND DISTRIBUTION OF THE 



aa. Teeth ou operculare; premaxillaries 8. 



Mandibulars 21 ; from coronoid to angle much shorter than from former to sym- 

 physis ; groove below coronoid extending anteriorly ; muzzle shorter ; frontals plane, 

 parietals and occipitals concave ; canthus strong, . . . .schreibersii. 



aaa. Teeth on operculare, premaxillary teeth ten (9). 



Twenty-nine (four) mandibulars ; coronoid without groove below, much nearer 

 angle mandible than symphysis ; muzzle long, frontals narrow plane ; canthus not 

 strong, '■ .anguinus. 



I have retained the name of the original species for the last of these species, which 

 Fitzinger has called P. laurentii. Z o i s i i is the stoutest in proportion to the 

 length. P. c a r r a r a e is from Dalmatia, while the others are from Carinthia. A 

 specimen like P. xanthos t ic t us, but with nine premaxillary teeth, has been 

 named fieyeri, and one very near anguin us, with twenty-four mandibulars, has 

 been named heidingerii. 



CADUCIBRANCHIATA. 



It is customary to regard this group as presenting two types, one with, and the 

 other without pharyngeal fissures. But this feature is of no greater value than any 

 other, as the very nearly allied genera Protonopsis and Megalobatrachus differ in this 

 respect. 



A. An axial cranial bone (? vomer) in front of orbitosphenoids, and one form- 

 ing palatal surface in front of parasphenoid. Teeth on the outer anterior 

 margin of palatines. Urohyal and basihyals distinct ; two anterior cerato- 

 hyals connate. 

 I. Prefrontals and pterygoids present. 



Parietals prolonged laterally, not reaching prefrontals. Orbitosphenoid separated 

 by membrane from prootic. Vestibule wall osseous internally. Premaxillaries 

 consolidated. 



Carpus and tarsus cartilaginous. 



Vertebras biconcave. 



Neck with a pharyngeal slit. 



Occipital condyles on cylindrical pedestal. 



Mandible elevated in part by tendon passing over parietal bone, and arising from 

 atlas. 



Amphiumidje — Two genera. Amphiuma, Murtenopsis. 



The occipital condyles and temporo-cervical tendon are quite as in Desmognathus ; 

 they have not been previously described. In Amphiuma means there is a minute, 

 not articulated bone on the suture between the o. o. frontalia and prsefrontalia, in the 

 situation of a lachrymal. 



