Vol. I. Sun — Cambrian Faunas of North China 



Genotype: — Quadraticephalus walcotti Sun. 



(iv) 63 



Quadraticephalus walcotti Sun (sp. nov.) 



Plate IV, Figs. 6a-d. 



This species is represented by several cranidia and separated free cheeks asso- 

 ciated with it. 



The generic description of Quadraticephalus is based on this species, and there- 

 fore nothing need be added here. 



The species is characterized by the broad, sHghtly convex frontal border of the 

 cephalon, small eyelobe placed opposite the second pair of the glabellar furrow, subrect- 

 angular glabella with a pronounced median longitudinal ridge, the presence of a depres- 

 sion dividing the frontal limb on the median line of the glabella and the free cheeks with 

 their very broad strong genal spines. 



The specific name is given in honor of Dr. C. D. Walcott in recognition of the 

 great work done by him on the Cambrian Faunas of China. 



Horizon and Locality — Upper Cambrian: from Kaolishan limestone of Tai-A.n, 

 just below the foot of the Pagoda, i.e. the highest bed in that region (Coll. Y. C. Sun). 



Quadraticephalus? convexus Sun. (sp, nov.) 



Plate IV, Fig. 7. 



This species is represented by a broken central portion of the cephalon. Glabella 

 quadrate in form very convex; it is distinctly marked by a longitudinal ridge extending 

 from the furrow in the front of the glabella to the occipital furrow. It is also marked by 

 two pairs of the glabellar furrows. The first or anterior pair faintly impressed and twisted ; 



