1888.] 469 [Newell. 



Genus KIONOCERAS Hyatt. 

 This genus includes those Orthoeeratidae in which the longitudi- 

 nal ridges are more prominent than the transverse striae or ridges, 

 when these are present. They are smooth throughout their entire 

 length, equalling group 4 of M. Barrande. 1 



KlONOCEKAS COLUMNARE. 



Orthoceras columnare Hall, 20th Kept. State Cab., revised ed., p. 411, 

 plate 19, figs. 4 to 8, pi. 24, fig. 1. 



Shell straight, apical angle 7°, initial extremity and living 

 chamber unknown. The transverse section varies from broadly 

 elliptical to nearly circular. 



The septa are thin; concavity equals an arc of 115° to 120°, 

 this difference being due to compression ; distance of the septa is 

 a little less than one -fourth of the diameter of the shell. 



The siphon is large, subcentral, broadly elliptical, measuring 

 10 mm. in diameter where the shell is 55 mm. across. A longitu- 

 dinal section shows that it is tubular. 



The surface of the cast shows the longitudinal ridges, eighteen 

 in the entire circumference, with fine striae between them and par- 

 allel to their length! 



In the breadth of the intervals between the ridges, these Indi- 

 ana fossils resemble Kionoceras (Orthoceras) strix Hall (Pal. Ohio, 

 ii, pi. ix), but in other respects agree closely with K. columnare. 



Locality. — Wabash City, Indiana. 



Kionoceras strix. 

 Orthoceras strix Hall and Whitfield, Pal. of Ohio, ii, p. 149, pi. 9, fig. 3. 



Shell large, straight ; transverse section broadly elliptical ; ap- 

 ical angle 10°. 



Siphon subcentral, moderate size, smaller than in K. columnare. 

 A longitudinal section of the Indiana specimens gives no satis- 

 factory evidence of its character in the interseptal space. 



External markings strong, with fine longitudinal striae. 



This species differs from K. columnare in the more rapid increase 

 in size of the shell and in the smaller siphon. 



Locality. — Wabash City. 



i Proc. B. S. N. H., xxn, p. 275. 



