,-1. 



idil. 



ITS. 



the. 



TlIK ISATKACIIIA OK NOKTII AMKUICA. .')83 



This j;('iMis t'xliibit.s also an cvtcriial (corpus adiposiini, wliicli I liuvi? 

 not Ibiind in Caliiila, Kn^-ystorna, or any otluT };i'nn.s of llatradiia. 

 Each one is snUtrilicdral, tho apex icstin;;' ncai' the. extremity of the 

 t:ora<!oi<l, lh(* body lyinj; between the strata of tlie external and in- 

 ternal oblique muscles, alonj; the anterior marjiin of tiui '( oe of the 

 liver on eaeh si<le. 



There are some iin[)ortant skeletal characters found in this f^enus, 

 whose value is not yet clear. Thus the suspensoriuni is free, and inis 

 an antero posterior m(»venient on the i)ror»tie. This is due to the form 

 of the scpiainosal, which has no /.yji'omatie process, and is not united by 

 suture with the ijrordic. The (juadrate eartilaj;e is all that connects it 

 willi the cranium. A similar structure exists in ilreviceps and Calluhi 

 (Plate 7.">, li<;s. 1-2). The Irontoparietals arecoiissilied with each otlier, 

 us are also liie prefrontals. 



The liyoid apparatus is i)eculiar (Plate 5(5, lig. IS). The fourth cera- 

 tobranchials are ossified and proximally incurved, aii<l in close contact 

 with each other, thus surroundiui? the larynx in (Voiit. They are only 

 connected with the basihyobrancthial plate by mcmluane. The latter 

 lias a re<"irved transverse anterior margin, and sends a ])i()cess forwards 

 on eaci side to the incurved and thin ceratohyals. Tin; third (terato- 

 branchials are elongate and ossiiied distally. This kind of liyoid ap- 

 paratus further distinguishes the family Ilemisidn- tVoni all others. 



FIIiMlSTKltXlA. 



l{(Hilfn;;ci-, C.'al. IJiilr. Sal. ISrit. Miis., cd. ii, 1>-^ j ( iiiiniis (iaisl iccliiiiia); 

 l'irinist( Tiiia ami Kaiiilbniiia, (.'(iim-, (.'lii'('lc-Li«t N. Aiiici-. JJatr., 

 i;('l>til., 1"^7T: Uaiiiiui'iiiia and I'liiroiiiroiiiiia jil., Cope, \at . Ilisl. Ivcv., 

 ISd.-,. 



The families of this superfamily are the following: 



I. No tt'i'tli on llio inaxillaiy or inciiiaxillaiy lioiii's; 



I'ra'coiacoidci iiri'Sfiit ; sacniiii willi dilated t liaiij^iilar dia[>oidijsi's, coiilliioiit 



Willi eoccyfit'al styli' ; two lohi's of (he liviT. Ilrcricipilidd', 



rra'coiacoidci waiitiiiii; Narnim disliiict t'roiii (•0('C'yj;('al style, willi dilaled tii- 

 aii^^iilar (liai)oi)liyse.s ; two io'ies of the liver Eii<iii>iU>m'Hhv. 



I'ra'coiiU'oldei ine.seiit : Kaeiiiiii distinct IVoin eoeeyt^eal style, with dilated tri- 



iuigiilar diiipopliyses ; twooi' tlireo lolies of tlie liver ['hriinixrUhv. 



I'ra'coraeoidei present; saciinii distinet from eoeey^^cal style, with eyliiidiical 



dia[)()iiliy.ses; tliree lohe.s of (lie liver ih inhohalhlw. 



II. Maxillary and prLMnaxillary l)one,s toothed: 



I'ra'coraeoidei absent ; sacral diapoidiyses dilated ; niandililc cdontnlons 



('oiihylUlw. 



I'ra'coracoids i)ri'sent; yaeral diapophyse.sexjianded; niandihlo edentulon.s 



Dyscopli Ida: 



Pra-coracoid present ; Hternnin and oniosternnni wanting; three lobes of the liver; 



mandible edentulous Colostcthklw. 



l'r;ecoraeoid present ; sternum and onio.sternum jiresent, osseous; three lobes of 



the liver: mandible e{h'nlulons IlaiiiiJir, 



Pra'coraeoid jin'sent ; sternum styloid; siieral diaiiophyses cylindiie; mandible 



ilentifierous Ccrntohatmchidw. 



I i 



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