ORDER II 



AMMONOIDEA 





Paraprolecanites, Karp. ; Pronnrit,*, Moj>. . Fig. 

 Gemm. ; Am1>it<*, \Vaagen; Nrii>.<, .Mnjs. (Fig. 1157). 



Family 3. Medlicottidae. Shells mmpn->snl, di- 

 ooidal, and involute, with smooth or << .Mated -id-.-. and 

 often costated or tuU-irulated and channeled renter. 

 Ventral lobe entire in primith v >pe.-i.->, and tritid or 

 divided as in primitive Pronoritida< in more .-penalised 

 forms. First lateral saddles >imple 1-iit divided in primi- 

 tive genera, and acquire in Medlicottia through liyjn-r- 

 trophy and the development of marginal.- -xtraordinary 

 serrated outlines. Aperture as in Pronorit ///.-. 



; /v</-////v//<.,/ />..*. /'// 



Fio. 1159. 



Suture-line of M<'iUi<;,tti,i. prlntm, W;iagen. 

 Carbonlferons ; .Stilt Kange, India (after Waagen). 



Penno- Carbon if IT on s : 

 Sicily (aft.-r (J 



Sicanites, Gemm.; Promedlicottia, Karp. ; Propinacoceras, Gemm.; M'i!lic<>ttt<i, 

 Waagen (Figs. 1158, 1159). Permian. 



II. LOBITIDA. 



An isolated group resembling Anarcestidae through the phylogerontic contraction of 

 the living chamber, but sutures similar to those of Prolecanitidae. Saddles entire, but 



the lateral lobes are bifid in the young, un>t th>- 

 median marginals in these lobes, becoming /"///</ 

 by growth, are often nearly equal in size to flf 

 more primitive laterals in ephebic stages. Anti- 

 siphonal lobe bifid and otJur ilnrxul inflfHinii* 

 entire and similar to those of Prolecanitidae, 



\ ^ Sh ^ ~*^ / 



</ Family 4. Lobitidae. Only two primi- 



tive lateral lobes are developed in early m-anic 

 i.- 1(: . 1100. sub -stages; the others 



Lobite* deUMnoeepkalu,, Hauer sp. Upper arise l) >' hypertrophy of 

 Trias ; Sandling, near Aussee, Austria. A, /;, the SCCOlldarv marginal 

 External aspect, t', Median section. I), -, j-. i " i 



Suture-line, Vi- saddles, which subse- 



inently divide the primi- 

 tive lobes. Antisiphonal lobe bifid. Aperture in ephebic stage 

 normal and with slight ventral crests ; contracted and more or 

 less distorted in gerontic stage. 



Includes only Lobites, Mojs. (Figs. 1160, 1161), from the OissVan, Tyroh 

 Alpine Trias. 



III. ARCESTIDA. 



Conchs more or less smooth, involute, rarely discoidal, invariably Anan 

 similar to many of the preceding groups, but with more co//////o- */'////>>-. Finally in 

 Arcestidae and Cladiscitidae the prolecanitean outline surn'r,* at " ml.' only in the 

 peculiar straightness and uniform size of the lobes and saddle*. Tin- ft'ntin <>f mnno- 

 phyllic outlines in the inner saddles and in the dorsal sutures, as well as in the young 

 stages, occurs in some forms, however, even in these families. 



Fu;. 1101. 



fiitum, Miiiist. >p. 

 (Carniolan) ; St. 



