I i 



'i 



i ? 



I i 



m 



L'-' >-\ 



248 Hri.LirriN :!i, iimtmi) statks national mi'skiim. 



The Discoylossiilii' must be ivfiiudcd as tlio most inimitivc fiimil.v of the, 

 Amira, as it shows none of Ihcso peculiar modilicatioiis, and presents 

 tlio greatest resemhhinee to the sahiinaiiders in its riUs and opistlioe(el 

 vertebiii', and to other itriniitive tyix's in its split steninni. In the 

 aceompan.vinj,' diajirism these allinities are expressed, and a possilde 

 ph.vlogeny is indieati'd. That tlie hitter will prove lar;;el.v correct is 

 shown by the presence of I)isc(.-;h)ssidie in tiie Miocene beds of I'rnssia, 

 ]>articnhirly lu'ar P.onn. The paU'ontoh»},'y of the Salientia is, however, 

 very imperlectly known. 



i;;iiiiil:i'. CysliytiMlliiil.i'. S( :ii>liio|ii(l;i'. 



/ 

 KiiK,v«t<>niiil:i', ('ciiiliiUMiiMcliiil.i'. Il.vlid.i'. ' IWifoiiitlii-, 



\ • ! 



riir.viiiNciil,!'. I 



I / / 

 IVliMlvli.lii'. 



AstcropliryiliilM'. 



Disco" l()ssi(l:i', 



XtMioiiidii'. Pipidiiv 



The Arciferaand I>'irniisternia each exhil)it parallel inodili<',ations of 

 structure, wiiich may Ite represented as follows in tabular foi in : 



AiHii r.ii\. I'liiAiisn i!\i.\. 



I. \\ ith.iiit ticili. 



(1. Willi >:i(r;il <liiipii|ili,\ sis dilatt'd. 



t lirf\ ii'ipitidM-. 



lillfDIlid.'i' •? I'-llK.V-'<t'>lllid:i'. 



' l'Iir.viiiscid:i'. 

 fill. Siiii:il ili;ipn|dl,\ MS ex liiidlic. 

 iJfiidniplir.v nisrid.r Itciidndtiitidii'. 



II. Willi piriii:i\ill:ir.v and lii:iNiil:il',v tci'tll only. 

 (i. W'itii s:i( lal diapiipliysi's dilaUd. 

 IVdodytidj' » 



P.dnl,atid.f M'>'"'«M'l'i'l="- 



llylida.... S M'ophylida.. 



(1(1. Willi sacral diapopli.ssrs cn liiidiir. 



Cysti^nalliida' 



( Kanula . 

 III. Tt'clli ill Imtli jaws. 



(V. Sacral diapii|diyscs iiiit> dilated. 



Aiiip1ii''riatli(id(iiiti(1a' } ti . t \ i t ■ ^ 



,, ' " , Cerafol)atraeIiula\ 



IltMiiipuractidir' ) 



'^ ,1 ' 



V 



