GASTHIOCKRAS. 91 



Gastriogeras illinoisknsk xMillcr Miiil Gurley. 



PI. XVI 1, Ho-s. 0-8. 



IS'.H). (rtmlatlttx iUliwiscnxis, Miller and Gurley. HiiM. Illinois State Mus. Nat. 



Hist. No. 11, p. 42, PL V, tigs. 6-8. 

 ISitS. I'd I'ldegoceras illinoi sense, E. Haug, Etudes sur les Qoniatites, |). :^1. 



The following description is quoted from tlic paper by Miller and 



Gurley : 



Species medium size, subglobose, volutions moderately enlargino-, and pei'ipherv 

 broadly rounded. One specimen exposes part of three volutions, leaving the impres- 

 sion that a complete shell contained not less than six volutions. A transverse of a 

 volution is subcrescentiform, the horns being short and obtuse. The last volution 

 incloses all the inner ones, but leaves a rather large open umbilicus. The air cham- 

 bers are short and complicated. The outer shell is not preserved in our specimen. 



The septa are gastriocei-an in cliaracter, consisting of a paii- of venti-al 

 lobes divided by a l)lunt siphonal saddle, a principal lateral lobe, and a 

 broad, shallow, })oiuted, fuiniel-shaped auxiliary. The saddles are clul)- 

 shajied, and the ^'entral and first lateral lobes mucronate. 



This species certainly belongs in the same genus with (Tasfrioceras 

 kansasense Miller and Gurley, of which the writer has satisfied himself by 

 an examination of the types of the two. Hang referred this species to 

 Paralegoceras, but in the di'awing of the septa (the internal part was added 

 to the original drawing from a sketch of the type by Dr. Stuart Weller) it 

 is seen to lack the fourth external lolje that is characteristic of ParaJcf/o- 

 ceras, and to have the normal number of lobes, external and internal, 

 characteristic of Gastrioceras. 



Occurrence. — Upper Coal Measures, Montgomery County, 111. Type 

 specimen is deposited in the })aleontologic collection, Walker Museum, 

 University of Chicago. 



Gastrioceras kamsasense Miller and Gurley. 



PI. XVII, figs. 9-11. 



1896. Goniatites kansasensis. Miller and Gurley. Bull. Illinois State Mus. Jsat. 

 Hist. No. 11, p. Vi, PI. V. tigs. H-11. 



Shell small, subglobose ; whorls slowly increasing in size, depressed 

 helmet-shaped and deeply embracing, indented to half their height by the 



