aUfBRIAX FA UNA S OF CHINA— WA LCO TT. 9 7 



The largest head in the collection has a length of li mm., with the 

 same width at the })alpel)ral lol)es; a pyoidium 14 mm. in length has 

 a width of 20 mm. 



This species appears to be most nearly related to Ilhenurus eurek- 

 eri.'</'.'<," which occurs at the ))ase of the Ordovician in the Eureka 

 district of Nevada, but it diti'ers in the smaller palpebral lobes, which 

 are situated fai'ther back on the head; and it diti'ers from /. ceres in 

 its proportionately longer head. 



This species is ([uite widely distributed in the Upper Cambrian lime- 

 stone, in association with th(^ following trilobites: IJ'x/ninis e/ieti/s, 

 Menocejphalux. deprcKxns, Pi((jo(Ji<i hia^ J\ lofox, I*h/c/i<iKp!.s ceto. 



Formation and hicultfij. — Upper Cambrian, lower portion of the 

 Chao Mi Tien formation. At Chao Mi Tieti; 7.5 miles east of Chao 

 Mi Tien; at Pagoda Hill, 1 nnle west southwest of Tai An F\i; and 

 two-thirds of a mile w^^st of Tai An Fu, Shangtung, China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



ILL/ENURUS CERES, new species. 



Head, exclusive of the free cheeks, rounded subquadrate, moder- 

 ately convex; the posterior margin of the head curves slightly upward 

 opposite the glal>ella, where there is a slight thickening which gives 

 the appearance of a narrow occipital ring; the front maigin of the 

 head is broadly curved. Glabella very faintly outlined on the interior 

 of the cast; as thus shown it has a width at the base of (> mm. and at 

 the front of 4. .5 mm. on a head 11 mm, in length; its somewhat rounded 

 front is about 1 nun. from the frontal rim of the head; no traces of 

 glabellar furrows have been observed, and in only one specimen can 

 the very faint dorsal furrow that outlines the glabella be seen. 



Fixed cheeks of the same specimen 3 mm. in width at the palpebral 

 lobes, from which they extend with almost uniform width to the front, 

 and broaden slightly backward before merging into the short, trian- 

 gular postero-lateral limbs; palpebral lobes small and situated back of 

 a line passing through the transverse center of the head. 



The associated pygidium in the same fragment of rock is rounded 

 subtriangular in outline, moderateh" convex, and without an}- indica- 

 tion of an axis except a very narrow, slightly marked median ridge on 

 the cast of the interior; a specimen 11 mm. in length has a width 

 of 16 mm. at the front margin; a very slight elevation of the front 

 margin near the center indicates that the axial lobe of this specimen 

 had a width of about mm. 



Surface minutely but not closely punctate under a strong lens. 



" Mon. U. S. Geol. Survey, VIII, 1884, p. 97, pi. xii, figs. 4 and 4«. 

 Proc. N. M. vol. xxix — 03 7 



