Newell.] 472 [Jan. 18, 



crenulations, not represented in the figures, appear on the base 

 of the living chamber. 



This species is founded upon several casts of living chambers, 

 all devoid of test. 



In the type specimen above figured the three greatest dimensions 

 are : — dorsi-ventral diameter of base of living chamber, 47 mm. ; 

 lateral diameter 42 mm. ; vertical, 55 mm. 



The species resembling this most nearly are G. rectum Barr. 

 (Bohemia EtageE,) and among American forms O. scrinium Hall. 

 From the latter G. Wabashensis differs in being more nearly coni- 

 cal ; that is, the horizontal sections decrease in size from the base 



Compressed iorm of Gomphoceras Wabashensis X h 



of the living chamber up towards the apertures, while in 67. scrin- 

 ium the outer chamber swells slightly above the base and then 

 decreases in area of horizontal section. The aperture also in 67. Wa- 

 bashensis is more nearly T-shaped, the median lobes coming so near 

 together as to reduce the vertical portion of the aperture to a thin 

 slit, while the aperture of G. scrinium approaches more nearly to 

 the type of Acleistoceras (Hyatt). 



Locality. — From the limestones at Harley Bros, quarry, Del- 

 phi, Indiana. 



Closely allied to this species, and probably differing mostly in size 

 and manner of preservation, are several specimens from Wabash 



