HISTOKY OF CLASSIFICATION OF AxMMONOIDS. 21 



Quite lecenth' G. von Arthaber" has redescribed the Permian fauna of 

 Djulfa in Armenia, making known the ^^I'^sence in tlie same beds of 

 Productus, Gastrioceras, Otoceras, and Hunf/aritcs; the two latter ammonite 

 genera are known elsewhere only in the Trias, and the beds containing 

 them are considered as uppermost Permian, later even than the Upper 

 Productus limestone of the Salt Range. 



When tliese new discoveries began to be known, it became evident 

 that a new classification of the Paleozoic ammonoids was necessary, since 

 there was no place in the old scheme for the new forms. The first 

 attempt to give a phvlogenetic classification of ammonoids, showing the 

 relationship of the goniatites and the ammonites was made by Steinmami,'' 

 but tliis was largely speculative, not based on the ontogeny of any species, 

 and hence fails to express the true relationships of the groups. 



The most satisfactory attempt at a phylogenetic classification of the 

 Paleozoic ammonoids is that of E. Hang,'' in -wdiich all known genera are 

 grouped in five phyla, or superfamilies: (I) Anarcestid.e, including 

 Ana>-eestes, Pnrodocems, Prionoceras, Prolohites, Mceneceras, Sporadoceras, 

 Dimeroceras, Pharciceras, ! Sandherf/eroceras, f Tricenoceras ; (II) GiiYPHio- 

 CERATiD.E, including Pericydus, Iluensteroceras, Gh/phioceras, Goniatites 

 s. str., Gastrioceras, Paralegoceras, AgatJiiceras, Adrianites, Stacheoceras ; 

 (III) Agoniatitid.t:, including Gyroceras rr \_3Ii)noccras'], Agoniatites, Tor- 

 noceras, Pinacites, Aganides ■:=i\Brancoceras Hyatt], f Pronannites, Dimor- 

 plioceras, Thalassoceras, Popanoccras ; (IV) Gephyroceratid.e, including 

 Gephyroceras, Tmanitcs, Nomismoccras, BeJoceras ; (V) Ibergiceratid^e zi: 

 [Prolecanitidoi, in part of Hyatt], including Ihergiceras, Paraprolecanites, 

 Pronorites, Parapronorites, Propinacoceras, Medlicoftia, Daraelites, Prolecanites. 



On Table II, page 113, of Hang's work, is an attempt to show 

 graphically the relations of the Paleozoic ammonoids to each other and 

 to their successors of the Mesozoic. This classification is a distinct 

 improvement over that of Steiumaun, but also makes the mistake of 

 grouping together heterogeneous elements and separating forms that are 

 manifestly of near kinship. It also seems to the writer that there are too 



OF. Freeh and G. von Arthaber, Ueber das Palaeozoicum in Hocbarraenien und Persien (No. 4, 

 G. von Arthaber, Das Jiingere Palaeozoicum aus der Araxes-Enge bei Djulfa) : Beitr. Palaeont. und 

 Geologie Oesterreicb-Ungarns und des Orients, Vol. XII, No. IV, 1900. 



''Elemente der Paliiont. 



'' Etudes sur les Goniatites. 



