CLASS V 



CEPHALOPODA 



645 



tremities or dorsal sutures piodiiced and corresponding witli the inner parts of the 

 external sutures. 



Meekoceras }iyaitt (Fig. 1228); Nicomedites Tou\a (KonincMtes) ; Clypeoceras nom. 

 nov. (Aspidites Waagen), of whicli the type is A^idites 

 süperb US Waagen ^ ; Proptychües Waagen. Triassic. 



Family 16. Gymnitidae Waagen. 



Smooth, compressed, discoidal shells with rounded 

 venter in primitive forms, hecoming involute with acute 

 venter in specialised species. Septa not reaching ahove 

 the ceratitic steige of development in most genera, hut nof 

 remaining in the goniatitic steige in any known genera. 

 Sutures in specialised groups similar in convexity and 

 general aspect to those of the Pinacoceratidae, hvJ 

 having peculiar, highly inclined auxiliaries which ar- 

 developed apparently from marginals on the umhilical 

 sides of the saddles ; no corresponding adventitious 

 inflections. Siphonal saddle similar to that of Meeko- 

 ceratidae, and arms of the ventral lohe narrow. First 

 lateral saddles are dependent on, or attached to the 

 large siphonal saddles, and often simulate adventitious 

 saddles. 



Gymnites Mojs. (Fig. 1229); Buddhaites Diener; 

 Anagymnites Hyatt. Type A. {Gymnites) lamarcki (Diener), 

 Type P. (Plac.) sakuntala (Mojs.). Trias. 



Xenodiscus and Xenaspis Waagen. Permian and Trias. Ophiceras Griesbach (Fig. 

 1230). Trias. Flemingites Waagen (Fig. 1231). 

 Trias. Japonites Mojs. Trias. Europe and Asia. 



The Gymnitidae are commonly regarded as a 

 subfamily under the Ptychitidae, but they are 



Meekoceras 

 Lower Trias ; 

 Hyatt and Smith). 



Fig. 1228. 



muslibachanum, White. 

 Idaho. X 1/2 (after 



Paragymnites Hyatt. 



Fig. 1229. 



Gymnites palmai Mojs. Muschelkalk 

 Schreyer Alp, near Oosau, Austria. 



Ophiceras jacksoni H. and S. I.ower Trias 

 Idaho (after Hyatt and Smith). 



more probably an offshoot from the Lecanitinae, and through them from the 

 Gephyroceratidae. 

 1 The nairie Aspidites was preoccupied when Waagen usecl it, and a new one becomes necessary. 



