68 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



spine. The third segment from the posterior end of the thorax is 

 continued laterally into a long, backward extending spine. 



Pygidium semi-circular in outline. The axis is somewhat narrower 

 than the thoracic axis and is more nearly semi-cylindrical, standing 

 considerably higher than the side lobes. No rim is apparent except 

 in the specimens compressed in shale when the doublure leaves an 

 impression on the upper surface : the border flattens out and is 

 slightly concave. Three or four axial furrows and rings are usually 

 discernible, but they become successively fainter until indistinguish- 

 able. Those near the anterior edge have median tubercles similar to 

 those on the thoracic segments. Several pleural furrows are very 

 faintly visible on the lateral lobes back of the strong anterior one, 

 the margin of which is slightly thickened. 



Derivation of name. — Avev = without ; 0/)ta = border. 



Genotype. — Dolichometopus tontocnsis Walcott. 



Range. — Upper Cambrian. 



Observations. — Anoria dififers from Dolichometopus, the genus to 

 which the type species was first referred, in several important respects. 

 The glabella of Dolichometopus is definitely separated from the 

 fixed cheeks and frontal limb by a dorsal furrow passing all the way 

 around. The course of the facial suture is different. In Dolicho- 

 metopus it diverges in front of the eyes as well as behind and here 

 more rapidly than in Anoria. It is also not intramarginal except pos- 

 sibly for a short distance. The eyes of Dolichometopus are relatively 

 larger and more curved than in Anoria. 



The pygidia of the two genera are quite similar in general appear- 

 ance. Dolichometopus always has a distinct border. The axial fur- 

 rows are also distinctive in their course, which is straight across the 

 flattened axis and not curved as in Anoria. 



ANORIA TONTOENSIS (Walcott) 



Plate 18, figs. 15-28 



Dolichometopus tontocnsis Walcott, 1916, Smithsonian Misc. Coll., Vol. 64, 

 No. 5, p. 373, pi. 51, figs. I, I a-h. (Description and illustration of 

 species.) 



Anoria tontocnsis Walcott, 1924, Smithsonian Misc. Coll., Vol. 75, No. 2, 

 p. 54, pi. 9, fig. 2. 



The original description with the generic description and illustra- 

 tions present all that we know of the species. 



Formation and locality. — Upper Cambrian: (74e) Bright Angel 

 shale. Indian Garden Spring: (74) Nunkoweap ' Valley, Grand 

 Canyon, Arizona. 



