rilK ISATllACHIA (iV NORTH AMERICA. 



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latter liimily is, tlieieforo, between tlie Pletliodontidie and the Sala- 

 niandrida'. The AinhlyiStoniidie and Plethodondida^ may be tluis eoni- 

 pared with reference to tlie devehipmental character of the features 



whidi distin^nish tlieni. 



AMllLY.SrOMID.K. 



Superior. 



(.'iirpuH .'iiul tiirHua o.sspoiis. 

 rroiiinxilliiry foiitancllo closod. 



Inferior. 



O. i>tfr!if/oidi'um ppraistcnt. 



I'l.ETIIODONTID.K. 



Inferior. 



Ciirpns and tarsus carfil!i<;innns. 

 rnMiiaxillary fonfanolle open. 



Superior. 



O. plrri/yoiilcuiii olilitisratod. 



Tlie inferiority of some Piethodontidie is seen in tlie non distinction 

 of the di;;its ((Edii)ns), the tliinness of the ossiticatioii of the purietal 

 nioaihranc bones (Hatrachoseps), and in (Elii»ina the persistence of tiie 

 mcinbranons <;raninm by the limitation of llie i)arietal boiies to two 

 small oval lateral scales and the wide divarication of the pi)st(M'ior ex- 

 tremities of the frontals. 



The <(enera embraced in this family are as follows: 



Section I. Tlie toiij;iie attaclied from tlio central or |)nsterior pedii'el to IIk^ anterior 

 niari^in in narrower or wider liaiid. ( I'lelIioilitnt;i'.) 

 A. Two preniaxillary Ixnies. 



Dij^its I,"); maxillary lione rej^nlar, willi niimerons small teetli: parietals 



I'lilly osailiod Plclhodon. 



Uij^its 1, I ; maxillary as al)ove, paritstals fully ossifuMl IlimidKcliilium. 



AA. f)n(\ ]ireinaxillary. 

 (Y. Di<;it.s I, 4. 



Maxillary rei^ular, with small teeth ; parietals not ossified .. . nntrachosepn. 

 itt* . i)i^its I, 'i. 



Maxillary normal ; teeth Hiiiiill, very niiiner'^"s ; no preniaxillary fonta- 

 nel le SlervochihiK. 



Maxillary edentulous jiosteriorly, decnrved, formin}:;aeiittinj^odij:e ; teeth 



few, larpe, Iviiife-shapeil ; a iiremaxillary fontanello iuloilnjr. 



Section II. The ton;;ne free all round; attached hy its central pedicel only. (Sjie- 

 leipes.) 

 A. Two preniaxillary bones (with fontanolle), 



I)i};its 4, 5. closely united hy a broad palmar membrane Cenlriton. 



I)ij.;its 4, r>, entirely fivf Gjiriiwjihilii.'i. 



AA. Olio preniaxillary bone (with fontanelle). 



(>•. ni^its 4. 4. ' 



Dijfits free ; parietal and palatine bones well ossified MiUiruhii^. 



liiY. Dijiits 4, ;'). 



!>i^itsall free; craMal bones well ossified S/iclcrprs. 



Dijiils little distinct: ]>ari<'tal and palatii'e cartila^jes not OHsilie<l. 



(J'dipitiii. 



I)i;;ils entirely confuundcd as an uinlividcd palm or sole ; cranial bones 



wcl 1 ossi tied (I'dipus. 



T\u\ {generic relationships of the above-named {jroi'ps are exceed- 

 inj^ly simi>le, ;uid the case with which the atiimalscan be analyzed ren- 

 ders the ciisc free from the donbts which constantly arise in discus- 

 sions of {generic relationships as to the probable omission of characters 



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