oKDKK II 



AM.MONOIDKA 



< '.ill/,-,,,-, //>.-, gen. no\-. Type ' '. A 111 in. //.///.( ////.;. sii.-u-ji ip. ; Metacanthoplifaj getL 



nov. (Fig. 1232). Type 



.V. (J.MW.) rhotiniKi - 



i/ofs/X d'Orb sp. Cre- 



taoeous. 



Family 35. Peroni- 

 ceratidae. Similar to 



M<( in iilit i<lii>> in general 



aspect and ornamenta- 

 tion of adult stage, l>ut 

 young liave a distinct 

 kci-1 and a coi-oiiatt- funn 

 with lu-avy 

 ('istai- gt'iicrally 

 tomous,and vciitt-r i 

 lias channels or 

 zones on either >idc of 

 the keel. Sutural out- 

 lint-s n iore complex than 

 in M<i in initidae. 



Peroniceras, Gau- 

 thiericeras, Gross. ; Hy- 

 strichoceras, gen. nov. 

 (Fig. 1233). Type H. 



(Amm.) Coupei, Brongt. sp. ; Dipoloceras, gen. nov. (Fig. 1234). 

 cristatum, d'Orb. sp. Cretaceous. 



Family 36. Prionotropidae. Young resemble some forms of Mn mm ///W<, luit 

 have a crenulated keel at an early stage, which is persistent. Costae usually liner and 



Metacanthoplitea 



(after Quenstedt). 



FIG. 1232. 

 Rhotomagense, Uefr. sp. 



Fninct- 



Type I >. (Amm.) 



Cenomanlan ; 



Fi.i. 1--34. 

 i-,-;.itntii)ii, Deluc sp. l.( 



Hystrichocenu variant 



Quedlinburg, Saxony. 



more closely set, and tubercle.- -mailer than in that family. Spines l.ecmne very large, 

 volutions more quadrate in section, and venter Hat with prominent keel and channels 

 until a late stage. Dorsal sutures reduced in discoidal forms to one pair of large 

 saddles and one of incomplete lobes on either side of the ontisiphonaL 



Prionotropis, PrionocyduS) Mortoniceras, Meek; Sctdonbackia t Xeum. ; Type N. 

 Germari, Eeuss.). Cretaceous. 



