ORDER II AMMONOIDEA 563 
Paraprolecanites, Karp.; Pronorites, Mojs. (Fig. 1156); Parapronorites, Daraelites, 
Gemm. ; Ambites, Waagen ; Norites, Mojs. (Fig. 1157). 
Family 3. Medlicottidae. Shells compressed, dis- 
coidal, and involute, with smooth or costated sides, and 
often costated or tuberculated and channeled  venter. 
Ventral lobe entire in. primitive species, and trifid or 
divided as in primitive Pronoritidae in more specialised 
forms. First lateral saddles simple but divided in primi- 
tive genera, and acquire in Medlicotiia through hyper- 
trophy and the development of marginals extraordinary 
serrated outlines. Aperture as in Pronoritidae. 
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Fic. 1158. 
MIG 5o. e a Ny . ‘ 
Fic. 115 Medlicottia Trautscholdi, Gemm. 
Suture-line of Medlicottia primas, Waagen. Permo- Permo-Carboniferous; Sosio, 
Carboniferous ; Salt Range, India (after Waagen). Sicily (after Gemmellaro). 
Sicanites, Gemm.; Promedlicottia, Karp. ; Propinacoceras, Gemm.; Medlicottia, 
Waagen (Figs. 1158, 1159). Permian. 
IJ. Lopirrpa. 
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, and the 
median marginals in these lobes, becoming larger 
by growth, are often nearly equal in size to the 
more primitive laterals in ephebic stages. Anti- 
siphonal lobe bifid and other dorsal inflections 
entire and similar to those of Prolecanitidae. 
Family 4. Lobitidae. Only two primi- 
tive lateral lobes are developed in early neanic 
sub-stages; the others 
Lobites delphinocephalus, Hauer sp. Upper ESS by hypertrophy ot 
Trias; Sandling, near Aussee, Austria. 4, B, the secondary marginal 
External aspect. C, Median section. D, : we ; 
Suture-line, 1/;. saddles, which subse- 
quently divide the primi- 
tive lobes. Antisiphonal lobe bifid. Aperture in ephebic stage 

Fic. 1160. 2 

normal and with slight ventral crests; contracted and more or ee 
Aaland = > se Lobites pisum, Miinst. sp. 
less distorted in gerontic stage. Keuper (Carniolan); St. 
Includes only Lobites, Mojs. (Figs. 1160, 1161), from the Cassian, Tyrol. 
Alpine Trias. 
III. ARcESTIDA. 
Conchs more or less smooth, involute, rarely discoidal, invariably Anarcestes-like, 
similar to many of the preceding groups, but with more complex sutures. Finally in 
Arcestidae and Cladiscitidae the prolecanitean outline survives as a rule only in the 
peculiar straightness and uniform size of the lobes and saddles. The retention of mono- 
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. 
