60 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxix. 



MENOCEPHALUS ACERIUS, new species. 



This species is represented by a single specimen of the glabella, fixed 

 cheek, and frontal limb. The glabella is moderately convex, broadly 

 triincato-conieal in outline, and marked b}" two pairs of faintly impressed, 

 short furrows; the sides approach each other slightly toward the 

 broadly rounded front; occipital furrow rounded and distinct; occi- 

 pital ring moderately convex and a little wider than the occipital 

 furrow; dorsal furrow well defined. 



Fixed cheeks, convex, about two-thirds the width of the glabella; 

 the}^ slope rather rapidly downward to the frontal rim and less so to 

 the postero-lateral limb; ocular ridge not distinctl}^ defined; palpebral 

 lobes small; frontal rim separated from the glabella and fixed cheeks 

 by a strong, narrow furrow; the rim is rounded and of about the same 

 width as the occipital ring. 



Surface covered with pustules perceptible to the unaided eye. The 

 head of the type specimen has a length of 10 nmi. ; the frontal rim and 

 occipital ring are each about 1 mm. in width. 



This species is referred to the genus Menocephalus on account of 

 the small palpebral lobes, pustulose surface, and the absence of a 

 frontal limb. It difi'ers from the type form in having a less convex, 

 more elongated glabella. 



Formation and locality. --MX&dXe, Cambrian, upper portion of the 

 Chang Ilsia formation, in a coarse, gra3'ish limestone; a mile east of 

 Chang Hsia, Shangtung, China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



MENOCEPHALUS ACIS, new species. 



Glabella prominent, convex, narrowing slightly from its base 

 toward the broadly rounded front; occipital furrow narrow, deep, and 

 separating a rather strong, rounded, occipital ring; dorsal furrow nar- 

 row and strongly defined. 



Fixed cheeks about one-half the width of the glabella, moderately 

 convex to the base of the palpebral lobe; posteriorly they slope rapidl}" 

 to the furrow within the posterior margin; anteriorh', rapidly to the 

 frontal rim; palpebral lobe small and somewhat elevated; frontal rim 

 narrow, rounded, and separated from the glabella by the narrow dor- 

 sal furrow. 



Surface marked by rather strong scattered granules. The only 

 specimen representing this species has a length of 5 mm. 



This species is characterized by its narrow, wire-like frontal rim 

 and the scattered granules on its outer surface. 



