(iv) 30 Palseontologia Sinica ^^'^- ^- 



1913 Dorypyge richthofeni Dames, Walcott, Research in China. Vol. Ill, p. 108-1G9 pi. 8 fig. 31 a-f. 



Doctor Dames gives a detailed description of this species. This species is most 

 common, being found everywhere in the Changhia Hmestone of North China. 



Doctor Walcott points out the following differences between Olenoides and 

 Dorypyge : 



(a) The glabella of Olenoides expands toward the front, while that of Dorypyge- 

 contracts in front of the pits in the dorsal furrow. 



(b) The pleural lobes of the pygidium of Olenoides have broad, shallow 

 furrows with sharp, narrow ridges separating them, while those of Dorypyge have narrow 

 furrows with broad, rounded ridges between them. The type of Olenoides, 0. nevadensis, 

 has a finely granulated surface, and the type of Dorypyge a coarsely granulated surface. 



This species is characterized by a high arched glabella, narrow uptuned frontal 

 border, presence of a large distinct occipital node, pustulose character of the surface; and 

 a pygidium with spinose margin and with two large strong outward and backward poin- 

 ting spines of the postero-lateral margin. 



Measurements : — 

 Cranidium 



Length of cranidium 

 Anterior width of cranidium 

 Posterior width of cranidium 

 Length of glabella 

 Width of occipital' ring 

 Pygidium 



Length 



Anterior width (exclusive of spines) 13.0 mm. 



Posterior width (exclusive of spines) 8.0 ram. 



Length of axial lobe 6.5 mm. 



No. 519 

 13.0 ram. 

 12.0 mm. 

 20.0 mm. 

 10.0 mm. 



2.2 mm. 



No. 520 

 10.0 mm. 

 15.5 mm. 

 10.5 mm. 



8.5 mm. 



Horizon and Locality: — Middle Cambrian: from Changhia limestone of 

 Cheng-shan, 8 li from Chao-Kou-Chuang. Collected by University excursion in 1923. 

 under the direction of the author. 



