170 INFERIOR OOLITE AMMONITES. 



1846. Ammonites eadians depeessus, Quenstedt. Ceph., pi. vii, figa. 4 a, h, 



only. 

 1850. — CoMES&is, d'Orbigny {non von Buch). Prodrome pal. stratigr., 



vol. i, p. 24-5. 

 1853. — — Chapuis ef Dewalque {non von Buck). Foss. Luxem- 



bourg ; Mem. cour. et Mem, des sav. etraag., 

 torn. XXV, pi. viii, fig. 4 ; pi. ix, fig. 1. 

 1856. — Thouaesensis, Oppel. Juraf., p. 248. 



1858. — EADiAisrs depeessus, Quenstedt. Jura, pi. xl, fig. 14. 



1874. — Thouaesensis, Dumortier. Etudes pal. Bassiu Rhone, 4e 



partie, p. 63. 



1878. Geammoceeas Thouaesense Bayle. Explic. carte geol. France, pi. Ixxviii, 



figs. 3—5. 



1879. Haepoceeas STEiATULTJM, franco. Unt. Dogger; Abh. geol. Spez.-Karte 



Elsass-Lothringen, Bd. ii, Heft 1, 

 pi. i, figs. 1 — 3. 

 1881. — EADIANS, Meneghini {non Beinecke) . Foss. du Medolo ; Pal. 



Lombarde, 4e serie, App., pi. i, fig. 8 (?). 

 1884. — STEiATULUM, var. comptum, Haug. Nouvelles Amm., Bull. 



Soc. Geol. France, 3e serie, t. xii, pi. xv, 

 figs. 2a,h{di form with joined ribs). 



1884. — — Wright. Monogr. Lias Amm. Pal. Soc, pi. 



Ixxxiv, fig. 4 only. 



1885. — — Saug. Beitr. Monogr. Harpoceras, Neues 



Jahrbuct fur Mineral ogie, &c., iii 

 Beil.-Bd., p. 611 (pars). 

 1885. Ammonites eadians depeessus, Quenstedt. Amm. Schwabischen Jura, 



pi. li, figs. 5 and 12 only ; pi. Iii, figs. 



1 and 2 only (non pi. liv, figs. 15 — 17). 



Discoidal, compressed, evolute. Whorls low, subquadrate, ornamented with 

 ventrally-projected, subarcuate ribs which often rise at the inner edge, but are 

 also at times inconspicuous on the inner third of the whorl, thus leaving a plain 

 band ; they are largest at the point of curvature on the edges of the ventral 

 and lateral areas. Ventral area, sometimes, more especially in smaller specimens, 

 flattened, with a depressed band or rudimentary sulcus on each side of the carina ; 

 at other times, and in more adult specimens, it is sloping. Carina solid and 

 small, less distinct in the adult. Inclusion slightly variable, but never great. 

 Umbilicus large and open, a little more depressed in the centre. Termination 

 of the adult a plain sigmoidal bend. Suture-line yqyj simple ; a siphonal and 

 lateral lobe of about equal length, a small superior lateral lobe, and no auxiliaries. 

 The inner whorls of this species present us with the following facts : — 

 What Hyatt calls the Goniatite-stage is depicted in PL XXVIII, figs. II — 13. 

 To this succeeds a smooth stage reminding us of Psiloceras, and the smooth inner 

 whorls of Arnioceras. The shell is now becoming more evolute, the ventral area 



