66 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 



parallel-sided, with a distinct furrow even on outer surface. Genal 

 spine slightly curved, of moderate length. Free cheek as in other 

 species of the genus. Surface of test perfectly smooth ; internal impres- 

 sions show fine anastomosing lines on frontal area and free cheeks. 

 Length of largest cranidium 8 mm. 



The pygidia attributed to the species are so similar to N. saffordi, 

 which occurs in the same beds, that some doubt remains concerning 

 their assignment. Pygidium somewhat fan-shaped, with regularly 

 curved pleurae and anterior margin. Axis prominent, long, tapered, 

 showing 3 rings plus a terminal section. Pleurae poorly fused, with 3 

 pairs of wide furrows and as many narrow interpleural grooves, all 

 furrows and grooves extending to the margin, where the separate 

 endings of the pleurae form a wavy outline. Border furrow and border 

 lacking. 



Discussion. — The cranidium resembles N. decUvis Resser, which 

 also appears to lack an occipital spine. However, this condition in the 

 type material in shale may be due to imperfect preservation, and there- 

 fore it was deemed preferable not to attempt identification with that 

 species. The pygidium resembles, besides A^. saffordi, pygidia associ- 

 ated with the type cranidia of N. kingstonensis Resser. All these py- 

 gidia strongly differ from those of other species of the genus, such as 

 N. walcotti and A^. halli illustrated herein, which have well-fused 

 pleural regions, a smooth posterior margin, and a border furrow, much 

 like pygidia of Norzvoodia. 



Occurrence. — Red beds at the base of the Nolichucky (Cedaria 

 zone) at locality end/ 1 (= U.S.N.M. loc. 27d). 



Types.— Uolotype: U.S.N.M. 144614. Paratypes: U.S.N.M. 

 144615. 



NORWOODELLA WALCOTTI Resser 



Plate 4, figures 16-23 



Norzvoodella walcotti Resser, 1938a, p. 89, pi. 10, figs. 42, 54. 



Available material. — The hypodigm consists of cranidia flattened 

 in shale. Good cranidia, free checks, and pygidia in limestone occur in 

 the U.S.G.S. and author's collections. 



Description. — Glabella entirely undefined on upper surface, except 

 for a faint indication of its anterior boundary. Occipital furrow obso- 

 lete; occipital ring extended into a slender, horizontal spine. Frontal 

 area undifferentiated, somewhat downsloping. Palpebral area, as de- 

 terminable on exfoliated specimens, very narrow. Palpebral lobes 

 small, somewhat elevated. Anterior sections of facial suture convergent, 

 making the frontal portion of the cranidium very narrow, well rounded. 

 Posterior section directed almost straight outward from palpebral lobe, 



