ORDER II AMMONOIDEA 581 
angles. Inner parts of sutures steeply inclined apicad, and dorsal sutures have a long 

Fic. 1212. 
Suture-line of Perisphinctes colubrinus, 
Rein. sp. 




. Fie. 1211. 
Erymnoceras coronatum, Brug. sp. Callovian ; 
Dept. Niévre, France. 1/3. 

pair of first dorsal saddles, usually two additional 
pairs of saddles, and two pairs of lobes. All of Fie. 1213. 
these are so decidedly inclined apicad that they — perisphinctes polyplocus, Rein. 
often appear as a single pair of complex saddles, Upper Jura; Pappenheim, Bavaria. 1/s. 
These genera are morphic equivalents of the Liassic Dactylioidae and are derived from the 
same common stock. Young 
have depressed trapezoidal volu- 
tions and often minute tubercles 
on ventro-lateral angles, but are 
otherwise smooth, like the young 
of Cadoceras subleve. They be- 
come compressed in neanic stage 
and rapidly assume the discoidal 
Perisphinctean form and costae 
without tubercles. 
Perisphinctes, Waagen 
(Grossouvria, Procerites, 
Choffatia, Siemirad.) (Figs. 
1212-1214); Ataxioceras, 
Font.; Proplanulites, Teiss. ; 
Pictonia, Bayle; Craspedites, 
Pavl. and Lampl.; Lithaco- 
ceras, gen. nov. Type L. 
(Aimm.) Ulmensis, Oppel sp. 
Inferior Oolite and Cretaceous. 
a a : r. } Family 17. Aspido- 
See RET ioe Jum, Gna sa ceratidae. Zittel, p-Pp- 
Earlier volutions  costated, 
later ones with one or two rows of tubercles, the inner row being developed first. 
Venter broad, never keeled. Sutures resemble those of Dactylioidae, but saddles 
and lobes broader and dorsal sutures with only one large pair of inner or first dorsal 

Fic. 1214. 
