NO. 1415. CAMBRIAN FAVNAS OF CHINA— WALCOTT. Tl 



The surface of the head, except the furrows, is thickl}' covered 

 with large pustules. A glabella 11 mm. in length (has a width of 

 8 mm. ; none of the specimens are sufficiently perfect to give meas- 

 urements for the entire length of the head. 



This species is characterized by the very narrow lixed cheeks and 

 strongly pustulose surface. It is associated with P. calchas. 



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

 Mi Tien formation, in a gray, somewhat coarse, fossiliferous lime- 

 stone; 2.7 miles southwest of Chao Mi Tien, Shangtimg, China. 



Collected by P^liot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



PTYCHASPIS CALCHAS, new species. 



Of this species only more or less imperfect specimens of the central 

 portions of the head, exclusive of the free cheeks, are known. Gla- 

 bella slightly convex on the posterior half and moderately convex at 

 the frontal lobe; it is divided by two transverse, rather strong, shal- 

 low furrows into two narrow lobes that arch slightly backward and an 

 anterior lobe that measures a little more than half the length of the 

 glabella; a pair of very slightly impressed and short furrows mark 

 the side of the frontal lobe a little ])ack of the center; occipital furrow 

 broad, shallow, and about the same strength as the two furrows cross- 

 ing the glabella; occipital ring narrow at the sides, increasing in width 

 toward the center, where it rises at the back above the general level 

 of the glabella; dorsal furrow broad and rounded. 



Fixed cheeks scarcely more than a very narrow ridge rising from 

 the })road dorsal furrow to the palpe})ral lol)e and sloping gently back- 

 ward into the postero-lateral limb and forward in front of the palpe- 

 bral lobe into the frontal border of the head; palpebral lobe about 

 one-fourth the length of the head and marked by a strong furrow^ 

 within the narrow rim; frontal limb nearly Hat, of medium width, and 

 sloping forward and downward from the dorsal furrow to the frontal 

 margin; postero-lateral limbs about as long as the width of the gla- 

 bella, and marked by a broad, shallow furrow within the narrow pos- 

 terior margin. 



The cast of the interior surface of the test appears to be minutely 

 punctate under a strong lens, and fragments of the exterior appear to 

 be smooth. The largest specimen of the head in the collection has a 

 length of about 22 mm.; a specimen 11 mm. in length has a glabella 

 5 mm. in width, with a fixed cheek a little less than 2 mm, in width 

 from the sides of the glabella across the dorsal furrow to the furrow 

 on the palpebral lobe. 



This species differs from the described species of the genus in the 

 low convexity of the glabella, the uniformity of the occipital and two 

 posterior furrows of the glabella, and the apparently smooth surface. 



