4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 95 



Available species indicate 15 thoracic segments. These specimens 

 also indicate that the genus had a rather simple and relatively small 

 pygidium in which the dorsal furrow only is well defined. 



Comparisons. — Comparisons should be made with Kochiella and 

 its allies, the chief distinguishing features being the convexity and 

 reduction in the brim. 



Genotype. — Ptychoparia teucer Walcott. 



Name. — avrcua = meet ; oy/xos = furrow. 



Range. — Lower Cambrian of the Appalachians and Cordilleran 

 regions. 



Antagmus teucer (Walcott) not Billings 



Ptychoparia teucer Walcott, U. S. Geol. Surv. Bull. 30, p. 197, pi. 26, fig. 3, 

 1886; loth Ann. Rep. U. S. Geol. Surv., p. 652, pi. 96, fig. 3, 1891. 



Lower Cambrian, Winooski; (loc. 25a) i^ miles east of Swanton, 

 Vermont. 

 Holotype. — U.S.N.M. no. 15436. 



ARMONIA Walcott, 1924 



Armonia Walcott, Smithsonian Misc. Coll., vol. 75, no. 2, p. 54, 1924; idem, 

 no. 3, p. 69, 1925. 



Confusion of species led to description of the genotype under two 

 specific and generic names. Consequently, the genotype for Armonia 

 must rest on the older name. 



This genus, like many others, is difficult to determine without whole 

 specimens, for the cranidium of Armonia is not easily distinguished 

 from that of Blainia or even Asaphiscus. However, the respective 

 pygidia differ so much that the retention of the several genera is 

 warranted. 



Diagnosis. — Trilobite as a whole ovate. Cephalon semicircular. 

 Glabella wide, tapered, nearly three-fourths the length of the head. 

 Posterolateral limbs wide, blunt. Suture anterior to eyes, which are 

 situated about the middle of the head, diverges moderately ; intramar- 

 ginal for some distance. Glabellar furrows faintly indicated ; occipital 

 furrow strong. 



Thorax with about 14 segments ; bluntly terminated. 



Pygidium somewhat triangular with a tendency toward extension 

 laterally of the anterior corners. Axis well defined, extending almost 

 to the rear margin. Pleural lobes well marked by both the pleural fur- 

 rows and grooves which extend practically to the margin. 



Comparisons. — Comparing Armonia elongata with Blainia gregaria, 

 it will be noted that the glabella of Armonia is somewhat longer and 



