DESCRIPTION OF GENERA AND SPECIES. 



lobes to the broadly rounded front. The palpebral lobes and posterior portions of 

 the cephalon are broken away in the only specimen known. 



This species is associated with Anomocarc minus Dames [1883, p. 15], from 

 which it differs in the character of the frontal limb and margin, in which respects it 

 also differs from Anomocarella tcmcnus [plate 20, fig. 7] and Anomocarella tatian 

 [plate 21, fig. i]. It may also be compared with the form from the St. Croix sand- 

 stones of Wisconsin, illustrated by James Hall as " Conocephalites diadematits" 

 [1863, plate 7, figs. 36, 37], from which it differs in having a convex instead of a con- 

 cave frontal rim. 



Formation and Locality. Middle Cambrian: (('!) Lower limestone member of 

 the Kiu-lung group [Blackwelder, 19070, pp. 37 and 39 (third list of fossils), and 

 fig. 8(7 (bed 33), p. 29], 3 miles (4.8 km.) southwest of Yen-chuang, Shan-tung, China. 



Coosia robusta Walcott. 



Plate 21, Figures 9, <)n. 



Consia robjista WALCOTT, 1911, Smithsonian Misc. Coll., vol. 57, No. 4, p. 97, plate 16, figs. 2, 2<z. 

 (Described and discussed as a. new species essentially as below.) 



Of this species the cranidium and pygidium are known. The cranidium differs 

 from that of C. snperba [plate 21, fig. 6] in having a proportionately more elongate 

 glabella, more convex frontal border, and narrower postero-lateral limb. 



The pygidium differs in being more elongate, in having a proportionately longer 

 axial lobe, and less flattened pleural lobes. 



Formation and Locality. Middle Cambrian: (1(17) Rome formation limestone 

 at Bull Run, northwest of Copper Ridge [Keith, 1896, areal geology sheet], 1 1 miles 

 (17.6 km.) northwest of Knoxville, Knox County, Tennessee. 



Collected by Cooper Curtice. 



Coosia superba Walcott. 

 Plate 21, Figures 6, 6a. 



Coositi siifrrba WALCOTT, 1911, Smithsonian Misc. Coll., vol. 57, No. 4, pp. 94-97, plate 16, figs, i, 

 id. (Described and discussed as a new species essentially as below.) 



Dorsal shield large, elongate-elliptical in outline; axial lobe of medium width, 

 conical, and narrowing from the cephalon gradually to the middle of the pygidium, 

 where it disappears. 



Cephalon semicircular in outline, moderately convex, genal angles unknown. 

 The facial sutures cut the posterior margin some distance within the outer margin 

 and extend inward and forward with a slight sigmoid flexure to the base of the 

 palpebral lobe ; arching about this, they extend downward and with a gentle outward 

 curve across the frontal limb and then curve inward across the broad frontal margin. 

 Cranidium with a rather large, subconical, moderately convex glabella that shows 

 very slight traces of lateral furrows. Occipital ring separated from the glabella by 

 a furrow that is rather shallow and nearly transverse; occipital ring slightly convex 

 and of nearly uniform width. Fixed cheeks narrow, about one-fourth or less of the 

 width of the glabella; posteriorly they merge into the large subtriangular postero- 

 lateral limbs, which are marked by a shallow, intermarginal posterior furrow; 

 anteriorly the fixed cheeks pass gently down and merge into the frontal limb. 

 Palpebral lobe small, less than one-fifth the length of the cephalon; it is continued 

 in a low ridge diagonally across the fixed cheek to the antero-lateral margin of the 

 glabella. Frontal limb less than one-half the width of the broad, gently convex 

 frontal border; in front of the glabella it slopes gently downward to a shallow furrow 

 that serves to distinguish it from the frontal border. Free cheeks unknown. 



