37 



41. Gomphoceras, Sowerby, 1839 



= Orthoceras (pars), Sowerby, 1812. 

 = Conilites, Pusch, 1837. 

 = Nelimenia, Castelnau, 1843. 

 = Bolboceras, Fischer, 1844. 

 =Apioceras, „ „ 

 = Poterioceras, McCoy „ 

 = Lituites (pars), Quenstedt, 1846. 

 = Syncoceras (pars), Pictet, 1854. 



42. Phragmoceras, Broderip, 1839 ... 



= Campulites(^ars) Deshayes,1830. 

 = Orthoceratites, Steininger, 1831. 



. Shell neither spiral nor linear. 



Shell straight, pear-shaped; aperture of 

 exterior chamber contracted, small and 

 lobed, the exterior chamber somewbat 

 globular ; position of siphuncle variable ; 

 from Silurian into Carboniferous. 



43. Ascoceras, Barrande, 1847 .... 

 = Cryptoceras, Barrande, 1846. 



44. Glossoceras, Barrande, 1865 



45. Aphragmites, Barrande, 1865 



Shell slightly curved, pear-shaped ; aper- 

 ture of exterior chamber contracted, 

 small and lobed ; siphuncle generally on 

 the internal (concave) side ; from Silu- 

 rian into Devonian. 



Shell slightly curved, flask-shaped, lower 

 portion more globular than the upper, 

 partitions of the chambers few and 

 rimning parallel to the long axis of the 

 shell, leaving a space the whole length 

 of the shell for the body of the creature, 

 aperture of exterior chamber not lobed ; 

 Silurian. 



Shell same as in Ascoceras, but with the 

 aperture of the exterior chamber lobed ; 

 Silurian. 



Shell same in general form as Ascoceras, 

 but without several internal partitions, 

 aperture not lobed ; Silurian. 



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

 1. Shell spiral in the same plane. 



46. Aturia, Brown, 1837. 



47. Nothoceras, Barrande, 1856 



The turns of the shell in contact over- 

 lapping ; 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. Cre- 

 taceous into Tertiary. 



Turns of the shell slightly overlapping, 

 siphuncle marginal, on convex (outer) 

 side, and furnished with internal radi- 

 ating 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, 1856 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 incom- 

 plete towards the final chamber, and 

 with a slight lobe, planned as in Notho- 

 ceras, aperture not lobed ; Silurian. 



