Q2 University of Texas Bulletin 



very near one. I wish to indicate that if it were not for the spiral 

 costae on the ventral part, one might be inclined to place the species 

 in Paraceltites; but in this latter genus the ventral portion is nearly 

 smooth and the transversal ribs disappear gradually between the ven- 

 tral shoulder and the sipho. 



On account of the imperfect state of preservation we avoid naming 

 this species. 



Age: 



Word formation, Permo-Carboniferous. 



Number of specimens examined: 

 One. 



Locality : 



Junction of Road and Gilliam Canyons, Glass Mountains. 



Schistoceras Hyatt emend. J. P. Smith 



The genus Schistoceras was established by Hyatt' for an unde- 

 scribed and unfigured species with a suture similar to that of Prole- 

 canites but differing from it by its large, bottle-shaped, median saddle 

 of the siphonal lobe. It has three pairs of lateral lobes and a small 

 umbilical lobe with two pairs of dorsal lobes, the two branches of the 

 siphonal lobe being widely separated. The lobes are hastate and the 

 saddles more rounded and club-shaped. 



J. P. Smith^ was the first to figure the type species {Schistoceras 

 Hyatti Smith) although Haug^ had already illustrated another 

 species (Sch. Hildrethi Mort.) of this genus, but considered it to be- 

 long to Agathiceras. J. P. Smith recognized the difference between 

 this latter genus and Schistoceras and explained it in the following 

 manner: "This genus undoubtedly resembles Agathiceras, but ap- 

 pears to differ in the constant number of lobes and saddles ; one exter- 

 nal lobe divided deeply by a bottle-shaped siphonal saddle, three lateral 

 lobes decreasing in length toward the umbilicus; a short pointed lobe 



'Hyatt, Gen. of foss. Ceph., p. 336. 



^J. P. Smith, Garb. Amm. of North America, p. 104. 



'Haug, Etudes sur les Goniatites, p. 105, pi. 1, fig. 40. 



