188 
should be treated at the time Agassiz recommended the inves- 
tigation to his pupil. 
Professor M. Nrumayr, of Vienna, has contributed an 
important memoir, Die Ammoniten der Kreide wnd die Systematik 
der Ammomiteden,* in which is brought into a continuous and 
connected form the progressive stages which the systematic 
study of Ammonites has made in the hands of the younger 
Palzontologists of the German school since the time Professor 
Suess called their attention to the subject, in his classical 
memoir Ueber Ammoniten, already cited in these pages. The 
works of Waacen, Mosgstsovics, Haver, Zrrre,, Laver, and his 
own important papers have all been put under contribution to 
bring the subject up to our present stand-point of knowledge. 
The Ammonites are grouped into four families :— 
I ARCESTID#. 
1 ArczsTEs, Suess. | 5 Prnacoceras, Mojs. 
2 DipymiTEs, Mojsisovics. 6 Saceceras, Mojs. 
3 Lopites, Mojs. | 7 AMALTHEUS, Montfort. 
4 PrycuiTEs, Vojs. 8 ScHLOENBACHIA, Neumayr. 
II TROPITIDA. 
12 Ruappoceras, Suess. 
13 CocHLoceras, Hauer. 
9 Tropites, Mojs. 
10 Tracuyceras, Laube. 
11 CHorIsTOocERAS, Mojs. 
III LYTOCERATIDZ. 
17 Bacuuitss, Lam. 
18 PHYLLOCERAS, Suess. 
14 Lytoceras, Suess. 
15 Hamirzs, Parkinson. 
16 Turritites, Lamarck. 
IV. AEGOCERATID &. 
19 ArncoceRas, Waagen. 
20 ARIETITES, Waag. ; 
21 Harpoceras, Waag. 
22 OprELiIaA, Waag. 
23 HapLoceras, Zittel. 
24 STEPHANOCERAS, Waag. 
25 CosmocEras, Waag. 
26 ANCYLOCERAS, d’Orbigny. 
27 Bacuuina, d’Orbig. 
28 SIMOCERAS, Zitt. 
* “Zeitschrift der Deutschen geologischen Gesellschaft,” p: 854; Jahr- 
gang. 1875. 
29 PERISPHINCTES, Waag. 
30 OLcosTEPHANUS, Neumayr. 
31 Scapuites, Park. 
32 Hopuitss, Newm. 
33 ACANTHOCERAS; Neum. 
34 SroticzKara, Neuwm: 
35 Crioceras, Léverilé. 
36 HETEROCERAS, d’Orbig. 
37 PELTOCERAS, Waag. 
38 ASPIDOCERAS, Zitt: 
