Il6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



rib inside of the anterior edge. A second and occasionally a third 

 rib may'be observed on the interior of the axis, especially in young 

 specimens. 



" Surface of test smooth or very minutely punctate." 



Observations. — ^Named after L. C. Wooster, the Wisconsin geolo- 

 gist, who collected most of the material from which this species was 

 worked out. 



Of all the known species, 5^. eurekensis (Walcott), doubtless 

 agrees best with 6". zvoostcri. For comparisons see the description 

 of the Nevada species. 



Formation and locality. — Ozarkian: (193) Oneota dolomite, in 

 partly decomposed white chert, about 15 feet (4.6 m.) above the base, 

 in Rudolph's quarry, at Trempealeau, Wisconsin. 



TAENICEPHALUS Ulrich and Resser 



Taenicephalus Ulrich and Resser in Walcott, 1924, Smithsonian Misc. Coll., 

 Vol. 75, No. 2, p. 59. 



This genus has been established to incude those forms which Hall 

 assigned to his genus Conaspis, that are congeneric with Conaspis 

 shumardi (Hall). 



The genus is characterized by the presence of glabellar furrows, 

 eye lines, medium-sized eyes situated well forward toward the front 

 of the glabella. Posterior to the eyes the suture diverges quite rapidly, 

 giving a broad base to this head. The suture diverges much less 

 rapidly in front of the eyes, and is intramarginal. 



Free cheeks are fairly large with a border more or less well defined. 



Pygidium with axial and pleural furrows, and a narrow rim. 



Derivation of name. — Greek Tau'ta= bound with a fillet; and 

 Ke^aA7; = head. 



Genotype.- — Conocephalites shumardi Hall. 



Range. — Upper Cambrian : Mississippi Valley and Rocky Moun- 

 tains. 



Observations. — Taenicephalus differs from Conaspis ^ in that the 

 fixed cheeks, palpebral lobes and border surround the glabella, which 

 is cut off square in front, as an elevated ridge. The facial suture is 

 intramarginal to the center, whereas it cuts the margin half way in 

 Conaspis. In Conaspis the posterior pair of glabellar furrows are 

 united across the glabella. The pygidium assigned to Taenicephalus 

 differs from that of Conaspis by having a flat rim, and this also 

 occurs along the outer edge of the free cheeks. 



^Hall, 1863, i6th Ann. Report New York State Cab. Nat. History, p. 152. 

 Walcott, 1914, Smithsonian Misc. Coll., Vol. 57, No. 13, p. 357- 



