8 



urLLF.TiN :m, uniteu states xational Ml-.-ElM. 



There are always a .listiuet so-oalle.l ceratohyal ; one ov moroaxia ele- 

 ments or basibranchials, aiul lateral pieces, or oeniiol.rancliials. liere 

 is no glossohyal. Further than this nothing can be said of the class, 

 as the orders' dilVer anion^' themselves in the details. 



In the carpus and tarsus there is always an os ccntrale, except in the, 

 tarsus of the Salientia. In the extinct Carboniferous yenera Evyops' 

 an.l Archcgosaurus.- there are two centralia in each foot (/>c.v ot Eryops 

 unknown). The intermedium is either present or fused with one of the 

 adjacent bones of the tirst row. There is a series of carpalia and of 

 tarsalia, pviny attachment to tlie met.'podials. whose nund)erand con- 

 dition ditfer in the dilVerent families, im' number of di-its is -onerally 

 not more than four in front and live behind. There is very often a rndi- 

 mental thumb on the anterior foot in the Salientia, and in the extinct 

 rhaehitomous jienus Eryoi)s there are live \vell-devcl(.i)ed dijiits on the 

 mauus. (Plate 1'). tiy'. 1.) In the .Salientia there is often a rudimental 

 sixth toe internal to the liallux. ( Plate 07-Si.) 



The shoulder-f,nrdle is not connected with the skull in the P.atrachia, 

 excepting in the genus Ilemisns. There is a large suprascapula. The 

 osseous coracoid is of various proportions, and it has various cartilagi- 

 nous extensions, as epicoracoid and procoraconl. These are ossilied in 

 some of the extinct forms. There is much variety in the pieces which 

 occupy the middle line of the scapular arcii. The (uders may be ar- 

 ranged as follows on this basis : 



An t'liisti'niuin amino sternum: UnnonphnUt. HhiuJutnuii 

 An oniosternnni and stenmni ; no ciiistfrniiin. SaVuntm. N- 

 Triichjintohuita, I'vote'ula, rrodtla (fxcejit TniiKitiiditui). 



The pelvis is always fiu'iiished with an ilium, but the pubis is want- 

 ing or represented by rudiments, except in the extinct forms, where it 

 is present. The ischium is i)riniitively an undivided cartilaginous plate. 

 Xo obturator foramen. There are some characters which are common 

 to all or nearly all Ijatrachia. but which may be found on further knowl- 

 edge of the extinct forms not ro have been always present. One of 

 these is the continuity or fixed articulation of tlie quadrate cartilage 

 or bone with the skull. The proximal part of this bone is intercalated 

 between the squamosal aii:l exoccipital. and the i»terygoid when present, 

 so as to i)resent only its distal extremity free. In the Salientia it is an 

 insignifleant element, being generally cartilaginous. 



The vomeroi)alatine bones are always double, except where wanting, 

 which is only the case in the Trachystomata. They are nearly always 

 deutigerous. 



The orbitosphenoid bone is always well developed. 



In the existing orders the atlas is undivided. I have put forth the 

 hypothesis^ that the vertebral bodies in the existing and most of the 



' Cope, American N'arurali>t, l-'T, ]). -136. ~" 



-Baiir, Carims u. Tarsus ,\nv Vcrrel)iatcn. 1--T. I5atnicliia. ]<\k <;-13. 

 'On the Intercfntnini >{ th.' Terrestrial Vertebrata. Transac. Anier Philosoi.li. 

 Soc, I^Sf), p. 34:!. 



'iiiilitihiiiu ri. StiijiHipiiali. 

 an sternal elements : 



1 



I 



'f 



^ 



.a 



4 



