l6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO3 



Honey Creek limestone; (loc. 12m) 7 miles north of Springer, 

 Arbuckle Mountains, Oklahoma. 

 Ifolotypc.—V.S.N.M. No. 108648. 



IRVINGELLA ALIA, new species 



Plate 2, Figures 42-47 



This species is represented by a few cranidia which are slightly 

 above average size. The glabella is wide and rounded off at the 

 anterior angles. All furrows are narrow but only moderately im- 

 pressed. The glabella stands wholly above the dorsal furrow. Later- 

 ally it is rather convex with a nearly even curvature, but longitudinally 

 the curvature extends from the rear margin to the front, increasing 

 slowly for half the distance and then more rapidly. The brim is 

 narrow and slightl}^ thickened. Fixigenes narrow, being a little more 

 than one-fourth the glabellar width. Their anterior angles turn down 

 into a vertical position. Laterally the fixigenes are slightly convex, 

 and slope down rather evenly from the dorsal furrow. The eyes are 

 very long, extending from the occipital furrow to the brim. 



Honey Creek limestone ; (loc. 9p) about 15 miles northwest of Fort 

 Sill, Wichita Mountains, Oklahoma. 



Holotype. — U.S.N.M. No. 108649a ; paratypes, No, 108649b. 



IRVINGELLA DAVISENSIS, new species 

 Plate 2, Figure 48 



The genus Irvingella is very poorly represented in the Davis forma- 

 tion of Missouri, this being the only species that can now be described. 



The glabella is rather narrow. The occipital furrow is wide and 

 deep, but the glabellar furrows are shallow. Laterally the glabella is 

 strongly convex, but not longitudinally. Brim is relatively wide and 

 convex. The fixigenes at their widest point are more than half the 

 width of the glabella at the same point. The anterior fixigenes are 

 somewhat wider than the brim. They rise slightly from the dorsal 

 furrow toward the eyes, then slope off gradually with increasing 

 convexity toward the outer edges. The posterolateral limbs are 

 sharply, and the anterior angles slightly, depressed. The eyes are of 

 moderate length. 



Davis formation ; (loc. 22m) Shaw Branch, Davis Creek, Missouri. 



Holotype.—U.S.^M. No. 108650. 



