110 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 



the present species, but an accurate comparison is difficult since all the 

 type material is more or less flattened. It would seem that Armonia 

 pelops has a proportionately narrower glabella and a more nearly tri- 

 angular pygidium. Metisia metisensis (Walcott) is almost identical in 

 the proportions and convexity of all the cranidial parts, but the surface 

 ornamentation is coarser, and the pygidium has a definite border and 

 is not turned down marginally as in the present form. 



Occurrence. — Uppermost beds of Maryville limestone (Cedaria 

 zone). Type locality cnc/2; also common at localities cnc/1, cnc/3 to 

 cnc/6. Also occurring in the red beds at the base of the Nolichucky at 

 locality end/ 1. 



Ty^^^.—Holotype : U.S.N.M. 144719. Paratypes: U.S.N.M. 144- 

 720-23. 



MODOCIA ? AGATHO ( Walcott ) 



Plate 1, figures 27-30 



Asaphiscus? agatho Walcott (part), 1916b, p. 391, pi. 63, fig. 9 (only). 

 Ehmania? agatho (Walcott) Resser, 1938b, p. 29. 



Available material. — Walcott based the species on the holotype 

 cranidium and assigned to it a pygidium on the same piece of limestone. 

 The author's collections, however, indicate that the pygidium belongs 

 to the more common, associated species Modocia dubia. A pygidium 

 believed to belong to the species is present in the collection from the 

 type locality. The author collected several cranidia and one pygidium. 



Description. — Glabella of moderate convexity, fairly straight-sided, 

 moderately tapered, rounded in front, with a bare trace of lateral fur- 

 rows on outer surface. Occipital furrow well marked; occipital ring 

 subtriangular, rounded. Frontal area downsloping, rather flat, divided 

 into preglabellar field and border by a shallow furrow, not accom- 

 panied by much change in slope. Ocular ridges present ; palpebral area 

 convex, on average horizontal, one-third the glabellar width. Palpebral 

 lobes 0.3 times the glabellar length, narrow, defined by shallow palpe- 

 bral furrow, situated at the level of glabellar midpoint and hence more 

 posterior in position than in the 3 preceding species. Anterior sections 

 of facial suture definitely divergent ; posterior section directed outward 

 from palpebral lobe, curving backward distally ; posterior area almost 

 parallel-sided, rounded distally, deeply furrowed ; surface smooth. 



Pygidium tentatively assigned to the species 2.2 times as wide as 

 long. Anterior margin fairly straight. Axis stout, not greatly tapered, 

 showing 2 rings plus a terminal section. Pleural regions with little con- 

 vexity, almost horizontal, showing several pairs of furrows and inter- 

 pleural grooves ; only the first pair of furrows fairly deep. All furrows 

 and grooves extend to a shallow border furrow that sets off a slightly 

 elevated border. Surface very finely granulate. 



