212 
THE LIAS AMMONITES. 
Division B. — Bdges of septa with a single marked fold. 
1. Shell spiral in the same plane. 
46. Aturia, 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, Barrandc, 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. Bathmoceras, 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. GoNiocERAs, Hall, 1847. 
Siphuncle marginal. Septa waved, shell compressed into an elliptic form j 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 foliated. Family, Goniatid^ (Barrande, 1867). 
Three Genera : Goniatites, Clymenia, and Bactrites. 
1. Shell spiral in the same plane. 
50. Goniatites, de Haan, 1825. = Nautilus, Lamarck, 1799. = Orbulites, 
Lamarck, 1801. = Aganides, Montfort, 1808. = Nautellipsites, Parkinson, 1811. 
— EUipsolithes (pars), Sowerby, 1812. 
