180 



THE LIAS AMMONITES. 



8. Vamily Clymenid^, Edwards, 1849. — Shell discoidal, more or less involute; septa 

 simple or slightly lobed ; siphuncle internal or coluraellar. 



Genus. — Clymenia, J/'it;2s^er, 1832. Endosiphonites, ^;««^e^, 1840. Shell spiral, 

 discoidal, with contiguous whorls, more or less involute ; septa form a distinct lobe on 

 the sides, with angles more or less acute ; siphon small, internal, situated against the 

 turns of the spire. Species numerous in the Devonian of Europe and N. America. 

 Ex. Clymenia SedgwicUi, Miinster (fig. 32) ; C. striata, Miinst. (fig. 33). 



Fig. 3 



II iinst. 



Fig. 33. — Clymenia striata, Miinst. 



Buh-order ^.— AMMONOIDA, Wright, 1880. 



Shell spiral, bent, or straight, with a capacious dwelling-chamber. Margins of the 

 septa angular, digitate, or much ramified, forming large lobes. Siphuncle marginal, 

 external with regard to the shell, or anti-columellar. This section is divided into three 

 Families, the Goniatites, the Ceratites, and the Ammonites. 



1. Family GoNiATiTiDiE, Wright, 1880. — Shell rolled into a close spiral; septa with 



angular margins. 



Genus. — Goniatites, De Haan, 1825. Aganides, Montfort, 1808. Shell spiral, regu- 

 larly rolled on the same plane, with convolute contiguous whorls. Septa transverse, 



Fig. 34. — Goniatites Hoenivghausi, 

 Bronn. 



Fig. 35. — Goniatites Orbii 

 d'Archiac. 



Fig. 36. — Goniatites rotatorius, 

 de Koninck. 



