212 THE LIAS AMMONITES. 



Division B. — Judges of septa with a single marked fold. 



1. Shell spiral in the same plane. 



46. Attjria, Bronn, 1836. 



The turns of the shell in contact overlapping ; siphuncle almost marginal, on concave 

 (inner) edge, and formed of a series of inserted cone-shaped partitions ; edges of the 

 partitions separating the chamber with a strong lateral lobe. Cretaceous into Tertiary. 



47. NoTHOCERAS, Barrande, 1856. 



Turns of the shell slightly overlapping, siphuncle marginal, on convex (outer) side, 

 and furnished with internal radiating plates ; septa with a slight lobe on the back of the 

 shell, corresponding in direction to that of the Ammonites ; aperture not lobed ; 

 Silurian. 



2. Shell straight. 



48. Bathmocebas, Barrande, 1867. 



Siphuncle marginal, containing a series of inserted cone-like partitions, whose points 

 are directed towards the final chamber, being the reverse of that observed in Endoceras. 

 Septa incomplete towards the final chamber, and with a slight lobe, planned as in Notho- 

 ceras ; aperture not lobed ; Silurian. 



49. GoNiocEBAs, Hall, 1847. 

 Siphuncle marginal. Septa waved, shell compressed into an elliptic form ; Silurian. 



IX. — Shell many chambered ; the last (exterior) chamber large ; siphuncle marginal ; 

 the edges of the partitions (septa), which separate the chambers, angulated or 

 waved, but not dentated or fohated. Eamily, Goniatid.® (Barrande, 1867). 

 Three Genera : Goniatites, Clymenia, and Bactrites. 



1. Shell spiral in the same plane. 



50. Goniatites, de Haan, 1825. = Nautilus, Lamarck, 1799. =: Orbuhtes, 

 Lamarck, 1801. :=: Aganides, Montfort, 1808. = Nautellipsites, Parkinson, 1811. 

 .:= Ellipsolithes (jjars), Sowerby, 1812. 



