238 
THE LIAS AMMONITES. 
" I. ArCESTIDjE. 
1. 
Arcestes, Suess. 
5. 
Pinacoceras, Mojs. 
2. 
DiDYMiTEs, Mojsisovics. 
6. 
Sageceras, Mojs. 
3. 
LOBITES, Mojs. 
7. Amaltheus, Montfort. 
4. 
Ptychites, Mojs. 
8. 
ScHLOENBAGHiA, Neumayv. 
II. TROPITIDiE. 
9. 
Tropites, Mojs. 
12. 
Rhabdoceras, Suess, 
10. 
Trachyceras, Laube. 
13. 
Cochloceras, Hauer. 
11. 
Choristoceras, Mojs. 
III. 
Lytoceratidj;. 
14. 
Lytoceras, Saess. 
17. 
Baculites, Lamarck. 
15. 
Hamites, Farkinson. 
18. 
xHYLLOCERASj ouess. 
Id. 
TuRRiLiTES, Lamarck. 
IV. 
Aegoceratid^. 
19. 
Aegoceras, Waagen. 
29. 
Perisphinctes, Waag. 
20. 
Arietites, Waag. 
30. 
Olcostephanus, Newmayr. 
21. 
Harpoceras, IFaag. 
31. 
ScAPHiTES, Parkinson. 
22. 
Oppelia, Waag. 
32. 
HopLiTEs, Neum. 
23. 
Haploceras, Zittel. 
33. 
Acanthoceras, Neum. 
24. 
Stephanoceras, Waag. 
34. 
Stoliczkaia, Neum. 
25. 
Cosmoceras, Waag. 
35. 
Crioceras, Leveille. 
26. 
Ancyloceras, d'Orbigng. 
36. 
Heteroceras, (TOrbig. 
27. 
Baculina, d'Orbig. 
37. 
Peltoceras, Waag. 
28. 
SlMOCERAS, Zitt. 
38. 
ASPIDOCERAS, Zitty 
Note. — The diagnoses of the families are here given in abstract from Prof. Neumayr's work. 
I. Family. — Aecestidj], Mojsisovics. 
Shell smooth or provided with transverse folds, ribs, or longitudinal lines. The wrinkle- 
layer (Runzel-schicht)^ present in the more ancient forms ; the lobes consist mostly of 
short, abruptly interrupted lines, seldom (only in Sageceras) granular. Mantle-impression, 
in the forms from the Trias, with more or less contraction around the mouth-opening 
^ This word has no equivalent in the English language, but it clearly means the wrinkled marginal 
layer of the mantle of the Mollusc, which formed the lobe-Hnes of the septa, and imparted such an 
important character to the shells of the Ammonitidifi. 
