62 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxix. 



Surface finely granulose under a strong lens, with a few scattered 

 larger granules. 



Formation and locality. — Middle Cambrian, upper portion of the 

 Chang Hsia formation, in a compact, hard, dove-colored limestone; 

 Chang Hsia, Shangtung, China. 



Collected b_y Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China, 



MENOCEPHALUS AGAVE, new species. 



Another species of Monocephalus is associated with M. adrastia^ in 

 which only the anterior portions of the head and one fixed cheek are 

 preserved. This difi'ers from M. adrastia in the proportionately nar- 

 rower glabella, rounded frontal rim, and less convex fixed cheek. Its 

 surface is very finely pustulose, with scattered larger pustules on the 

 glabella. The palpebral lobe is very small and situated a little back 

 of the center of the head. 



Formation and locality. — Middle Cambrian, upper portion of the 

 Chang Hsia formation, in a compact, hard, dove-colored bed; Chang 

 Hsia, Shangtung, China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



MENOCEPHALUS BELENUS, new species. 



This species is represented by a single specimen of a glabella, occip- 

 ital ring, and frontal rim. It difl^ers from If. acerius in having a 

 very narrow, slightly flattened frontal rim, and a very finely pustulose 

 surface. The glabella is also more conical and its front more rounded. 

 A fragment of the fixed cheeks indicates that they were rather convex 

 and rose somewhat abruptly from a distinct dorsal furrow. The gen- 

 eral remarks relating to the generic relations of M. acerius also apply 

 to M. helenus., as they are apparently congeneric. 



Formation and locality .—M.\didi\Q Cambrian, upper portion of the 

 Chang Hsia formation, in a bed above that containing 3L acerius; 

 Chang Hsia, Shangtung, China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



MENOCEPHALUS (?) DEPRESSUS, new species. 



General form of the head, exclusive of the free cheeks, subrhom- 

 boidal, moderately convex. Glabella moderately convex, narrowing 

 slightly from the base toward the rather broadly rounded front; sur- 

 face marked by two pairs of very shallow, short glabellar furrows; 

 occipital furrow narrow, transverse, and sharply impressed; occipital 

 ring slightly convex and of nearly uniform width; dorsal furrow 

 narrow and sharply defined. 



