,(iv) 76 Palxontologia Siidca Ser. B. 



"This species resembles Ptychaspis campe Walcott from the Upper Cambrian 

 Oh'aumitien limestone of Shantung in the form of the glabella, fixed cheeks and 

 palpebral lobes, and in the pustulose character of the carapace. The occipital furrow of 

 our species is however very much deeper than in that species, being moreover 

 continuous, while it is interupted in the center in the Shantung species. Our species is 

 more over nearly twice as large as P. campe. 



"Horizon and Locality: In the thin-bedded argillaceous limestone of 

 Fengshan formation of Yeh-Li, Luan-Hsien, Chihli, Collected by H. C. T'an. The 

 species is named after ]ilr. Y. C. Sun, of the National Geological Survey.' ' 



Ptychaspis acamus var. punctata Sun (var. nov.) 



Plate V, Figs. 5a-d. 



1905 Ptychaspis acamus Walcott, Proc. U. S. Nat. Mus., Vol. XXIX, p. 69. 



1913 Ptychaspis acamus Walcott, Research in China Vol. Ill, p. 179, pi. 16, Fig. 18, 18 a. 



1923 Ptychaspis acamus Walcott, San; Bulletin of the Geological Society of China. Vol. II, No. 1-2 p. 

 101 (listed). 



This variety is represented by six cranidia, and associated free cheeks. 

 Glabella strongly convex on the frontal lobe, but moderately convex at the back; 

 Subrectangular in outline with two sides parallel to each other; frontal margin of the 

 glabella very straight and separated from the uniformly narrow border by a straight 

 pronounced groove. Anterior lobe quadrate in form, mai-ked by two pairs of short 

 slightly impressed glabellar furrows; the posterior pair little longer than the posterior 

 ones, extending backward and inward for very short distance ; second lobe very narrow 

 antero-posteriorly about as wide as the occipital ring and separated from the large longer 

 anterior lobe by a broad strong backward arching furrow. 



Fixed cheeks very narrow about the same width as the frontal border. Dorsal 

 furrow deep and distinct. 



Frontal border narrow elevated and straight, of uniformly width throughout. 



Occipital ring narrow of uniform width throughout. 



Surface strongly marked by very large pustules and also finely punctated. 



As only the glabella of the type species is known, the detail comparison is not 

 possible. 



