V iii INFERIOR OOLITE AMMONITES. 



Denckmann, Fauna von Doernten ; Geol. Specialkarte von Preussea und den Thiiringisehen 



Staaten, Bd. viii, Heft 2, 1887. 

 Dumoetiee, Etudes pal. Ba^sin du Rhone, vol. iv, 1874. 

 GrOTTSCHE, Jurass. Verstein. ; Paheont., Suppl. 3, Lief ii, Heft 2, 1878. 

 Haueb, Ceph. N. O. Alpen ; Denksch. matb.-natur. Wisaensc'h., Bd. xi, 1856. 

 Haug, Nouv. Auiin. ; Bull. Soc. Geol. Prauce, 3e ser., 1884. 

 Meneghini, Lias superieur ; Pal. Lombarde, series 4, 1867. 

 Oppel, Jurass Ceph. ; Pal. Mittheilungen, 1862. 

 Oebignt, Ceph. Terr. Jurass.; Pal. franc., 1844. 

 Quenstedt, Cephalopoden, 1846. 



— Jura, 1858. 



— Aram. Schwab. Jura, 1885. 

 Retnes, Geol. et Pal. Aveyronnaises, 1868. 



— Monogr. Amm,, Lias sup., 1879. 

 Sowebbt, Mineral Conchology, 1815. 

 Weight, Lias Ammonites, Pal. Soc, 1882. 



These species of the Lillia-Haugia series may be arranged according to the 

 different characters which they possess. Thus at least five different characters 

 may be utilised for the purpose of a rough analysis. So a species is either — 



Latumbilicate 



or 

 Angustumbilicate 1 



— and there are further characters of distinction. 



A rough classification of the different species of the Lillia-Haugia series is 

 now attempted. It is attended with very considerable difficulty. In the first 

 place, it has not hitherto been considered necessary to figure the radial curve, and 

 so a most important character is wanting. Then there is a mechanical difficulty : 

 it is impossible to place side by side the figures of species contained in a number 

 of large volumes ; so that comparison is rendered extremely laborious, and at best 

 it is unsatisfactory. It is only possible to carry out the arrangement of the 

 species in a natural order by having figures of all specimens mounted on separate 

 slips, in order that they can be brought together in series in a small compass. But 

 this can only be accomplished either by re-drawing all the figures, or by cutting 

 up the plates of costly volumes ; and both these processes are out of the question 

 at present. But one or the other will have to be adopted if an exact classification 

 is to be obtained. 



However, the result of the comparison which I have instituted between the 



various species, and the analysis of their characters, is now presented. 



1 These terms are used comparatively with regard to species nearly in the same develop- 

 mental stage, — for instance, to express the distinction between the umbilication of Lilli and Bayani, 

 both costate species with the carinati-sulcate periphery retained. 



' 



Rursiradiate > 



Crassornate < 





Rectiradiate 



or 



or 



Reguhiri-ornate 



or 



- Versiradiate 



ornate 



or 



Flexiradiate 



or 



or 



irregulari-ornate 



. j 



Prorsiradiate . 



parviornate . 





