98 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxix. 



This sjiecies differs from /. crniens ])y the greater width of the heud 

 at the ])alpe})ral lobes and less convexity; the associated pygidiiini is 

 less convex, more subtriangalar in outline, and without the indication 

 of a central axis. 



The associated species on the same hand specimen are Ptueaxpix eeto 

 and Anomoccu'ella canne. 



Formation and locality. — Upper Cambrian, lower portion of Chao 

 Mi Tien formation, in gray, crystalline, fossiliferous limestone: Chao 

 Mi Tien, Shangtung, China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



ILL^ENURUS DICTYS, new species. 



Head, exclusive of the free cheeks, rounded, subquadrate, gently 

 convex; the posterior margin of the head curves slightly upward 

 opposite the central portion, where there is a slight elevation which 

 gives the appearance of a narrow occipital ring; the front margin of 

 the head is l)roadly rounded, with a very l)road obtuse angle at the 

 center; the cast of the interior of the crust shows a very faint, low, 

 longitudinal median ridge. The glabella is not defined from the fixed 

 cheeks. The palpebral lobes are small and situated nearly opposite 

 the center of the head; postero -lateral limbs small and short. 



Surface smoath under a strong lens. 



The associated pygidium is transverse, rounded, subtriangular; 

 froiit broadly rounded; sides gently rounded, forming a rounded 

 obtuse angle at the posterior margin; the cast of the interior of the 

 crust shows a narrow, slightly defined axis, wMth eight or more very 

 faint transverse furrows and rings. The pleural lobes are gently 

 convex and without any trace of furrows. 



A head 6 nun. in length has an equal width at the palpebi-al lobes. 

 A specimen of the associated pygidium T mm. in length has a width 

 of 8 nun. at the front margin. 



This species differs from lUivnurus ceres in the obtusely pointed 

 front margin of the head and its less convexity. From Illivinirxs 

 catteus it differs in the direction of the facial sutures from the front 

 margin back to the palpebral lobes; the sutures of JUa^nurus dicti/s 

 extend slightly outward from the base of the palpebral lobe to the 

 margin, while those of Itl^uurus canens extend directly forwaid, 

 making the central portion of the head narrower at the front margin. 



Formation and locality. — Upper Cambrian. Central portion of 

 Chao Mi Tien formation. Pagoda hill. 1 mile west and southwest of 

 Tai An Fu, Shangtung, China. 



Collected hy Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



