NO. 141.^ CAMBRIAN FAUNAS OP CHINA— WALCOTT. 69 



Genus PTYCHASPIS Hall. 

 PTYCHASPIS ACAMUS, new species. 



This species is represented by speciineiis of tlie <>labellu unci frag- 

 ments of the iixed cheeiis. The g-labclla is moderately convex at the 

 back and strongly convex on the frontal lobe. It is divided 1)\' a 

 strong-, backward-arching furrow that separates the posterior portion 

 as a transverse lobe and the anterior as a large lobe al)out as long as 

 broad. The latter is marked b}' two narrow, shoi't, slightly impressed 

 furrows on the sides of the lobe; occipital furrow strongly rounded, 

 deep, and arching forward at the center; occipital ring about the 

 middle of the posterior lobe of the glabella nearly Hat, and with a 

 small, sharp node at the center near the l)ack margin; frontal rim a 

 rounded, narrow border in front of the deep, narrow dorsal furrow; 

 dorsal furrow narrow and deep opposite the palpebral lobe. 



Fixed cheeks rise rapidly from the dorsal furrow. They are narrow 

 and convex; palpebral lobes unknown. The anterior lobe of the 

 glabella slightly overhangs the dorsal furrow, which is deep and 

 rounded. 



Surface marked with low, large pustules and very faint punctte. 

 The type specimen of the head in the collection has a length of 

 11 nun. with a width of G mm. 



This species is characterized by the form of the large front lo])e, the 

 strong transverse furrows, and narrow posterior lobe of the glabella, 

 and its peculiar surface. 



Fdi'ination and locality. — Middle C-ambrian, central portion of the 

 Chang Hsia formation; Chao Mi Tien, Shangtung, China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



PTYCHASPIS CACUS, new species. 



General form of head, exclusive of the free cheeks, subrhomboidal, 

 rounded in front, strongly convex. Glabella moderately convex over 

 the posterior portion, strongl}" convex at the frontal lobe; posterior 

 portion is divided into two lobes, of about equal width, by the broad, 

 rounded, transverse posterior furrow and a narrow, slightly impressed 

 anterior furrow, both of which arch slightly backward toward the 

 center; the frontal lobe is about as long as the two posterior lobes 

 and arches with uniform curve over to the dorsal furrow; it is eon- 

 vex but not globose; it is marked about midway on each side by a 

 short, very lightly impressed narrow furrow, which penetrates it at 

 right angles to the dorsal furrow; occipital furrow broad, strong, 

 and arching slightly forward at the center; occipital ring about as 

 wide as the posterior lobe of the glabella, moderatel}^ convex, and 

 arching slightl}^ forward near the center; dorsal furrow strongly 



