vi INFERIOR OOLITE AMMONITES. 



Hemer.tj: 



Witchelliss sp. 



Fuscse. 



Sonninise sp. 



Zigzag} 



Discitx. 



Truellii} 



Concavi. 



Qarantianse. 



Bradfordensis. 



Niortensis. 



Murchisonx. 



Blagdeni. 



Scissi. 



Sauzei. 



Opaliniformis. 



Aalensis. 



Moorei. 



Dumortierix sp. 



Disjjcinsi. 



Struckmanni. 



Striatuli. 



Variabilis. 



Lilli. 



Of these Hemerse so many form an Age, but that portion of the subject does 

 not require consideration here. 1 



Family— HILDOCERATID^E. 



The Lillia-Haugia series. 



At present a considerable series of species, to which certain titles have 

 been somewhat indiscriminately applied, are arranged under the two genera 

 Lillia and Haugia. The method of such generic distribution and its consequent 

 nomenclature is more influenced by shape than by questions of exact genetic 

 affinity. It is somewhat as follows : 



Haugia, platyleptogyral, somewhat angustumbilicate, more or less alticarinate 

 species. 



Lillia, stenogyral, latumbilicate, peripherally carinati-sulcate species. 



However, such characters belong to stages of phylogenetic development, — that 

 is to say, the biologically later Lillise would possess characters ascribed to 

 "Haugia;" the biologically earlier Haugise the characters given to " Lillia. " 

 Such characters, therefore, can only be taken relatively to other features, as to 

 what degree they are developed in proportion to the development of those other 

 features. 



The following is a list of the principal species which belong to the Lillia- 

 Haugia series, or are sufficiently similar to require consideration : 



Andittm, Harpocebas, Gottsche, PI. i, fig. 8. 

 Bayant, Ammonites, Dumortier, PI. xvi, figs. 7 — 9. 



1 Buckman and Wilson, " Dundry Hill," ' Quart. Journ. Geol. Soc.,' vol. lii, p. 669 ; and Table 

 IV, Ac, 1896. Also Buckman. ' Jurassic Time,' ibid., vol. liv, p. 442. 



