74 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxix. 



slightly overhangs the frontal rim; occipital furrow about as strong as 

 the two glabellar furrows; occipital ring narrow and slightly rounded, 

 and elevated at the center; dorsal furrows strong and deep on the 

 sides and in front of the glabella. 



Fixed cheeks with the dorsal furrow about two-thirds the width of 

 the glabella, the tixed cheeks forming an elevated ridge at the palpe- 

 bral lobe, with an elevated short ridge opposite the anterior end of 

 the palpe])ral lobe, that is crossed by three transverse ridges, as seen 

 in the cast of the inner surface; in front of the elevated portion the 

 cheek drops gently to the frontal rim; back of the palpebral lobe the 

 cheek slopes gently and merges into the postero-lateral limb; palpe- 

 bral lobe narrow, elongate, a little more than one-half the length of 

 the head, and separated from the tixed cheek by a narrow, deep fur- 

 row; postero-lateral limb about as long as the w^idth of the glabella at 

 the base, and marked by a broad, deej), rounded groove, within the 

 sharp, elevated, posterior margin; frontal limb very short and sloping 

 downward into the rounded frontal rim; the frontal limb and rim 

 form scarcely more than the outer border of the strong dorsal furrow. 



Outer surface unknown, as in all the specimens the test clings to 

 the matrix; this latter fact indicates that it was roughened, probably 

 tuberculose. The cast of the frontal lobe of the glabella shows a 

 number of irregular, concentric ridges and grooves sub-parallel to the 

 frontal margin. The largest head in the collection has a length of 14 

 nun., with a width at the palpebral lobes of 17 mm. ; the glabella was 8 

 mm. in width, with a length, including the occipital ring, of 14 mm. 



This species differs from Pfycliaspis caeus in the globose, overhang- 

 ing frontal lobe of the glabella, and the form of the frontal rim, fea- 

 tures that also separate it from P. cadmus and P. calchas. From P. 

 acamus it differs in the form of the frontal lobe of the glabella and 

 the transverse lobe back of it. The globose glabella resembles that 

 of P. granvlosa Owen, except that it is more globose and overhangs 

 the frontal border, P. (/ranuJosa has a different form from the other 

 Chinese species. 



Formation, and local Hy. — Upper Cambrian, in the lower portion of 

 the Chao Mi Tien formation, in a fossiliferous, coarse gray limestone. 

 Chao Mi Tien; two-thirds of a mile west of Tai An Fu; Pagoda Hill, 

 a mile west-southwest of Tai An Fu; 2.7 miles southwest of Yen 

 Chuang, Hsin Tai, Shangtung, China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



PTYCHASPIS, species undetermined. 



There are several species of Pfi/ehasjtJs that occur in the upper 

 C'ambrian zone that are too imperfect for description. One of these 

 has the general form of /■*. catn]>t\ ))ut it differs in the exceedingly 



