82 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxix. 



the eye lobes; at the front it slopes into the rounded groove back of 

 the narrow, slig'htly flattened, frontal rim. 



Surface slig-hlty roughened over the central portions; on the frontal 

 limb a network of tine, irregular, raised lines extends from the dorsal 

 furrow and ocular ridges to the furrow inside the frontal rim. 



()hservatio7is. — This species is associated with PtycJiojxiria Liostra- 

 cus thraso. Its strong frontal limb and occipital spine distinguish it 

 from other species. 



Formation and locality. — Middle Cambrian. Base of Chang Hsia 

 formation in oolitic limestone about 2 miles southwest of Yen (Jhuang, 

 and 1 mile east-southeast of Chang Hsia, HsinTai, Shangtung, China. 



Collected by Eliot Black welder, of the Carnegie Institution of 

 Washington Expedition to China. 



PTYCHOPARIA THEANO, new species. 



Head small, moderately convex; glabella subquadrilateral, mod- 

 erately convex, a little narrower in front than at the base, and with- 

 out glabellar furrows; occipital ring practically a continuation of the 

 glabella, as the shallow occipital furrow barely indicates it; dorsal 

 furrows narrow at the sides of the glabella, and very obscure in front 

 of it. 



Fixed cheeks a little wider than the glabella and nearly flat from 

 the dorsal suture to the palpebral lobes; palpebral lobes large, situ= 

 ated opposite the central portion of the glabella; ocular ridges low 

 and broad, and very clearly detining the lateral portions of the iixed 

 cheeks from the frontal liml); frontal linil) narrow^ in front of the 

 glabella, sloping downward to the broad, shallow furrow that merges 

 into the broad, almost flat, frontal rim; postero-lateral limbs short; a 

 narrow, sharp furrow extends along their posterior margin from the 

 glabella to the facial suture, just within the posterior margin. 



Surface minutely granular under a ver}^ strong lens. The largest 

 head has a length of 5 nun. 



This species is distinguished b}^ the broad, flat, rixed cheeks, con- 

 vex, smooth gla])ella, large palpebral lobes, and nearly flat frontal 

 margin. 



Formation and locality. — Middle Cambrian. Base of Chang Hsia 

 formation, in gray oolitic limestone. Chang Hsia, Shangtung, China. 



Collected by P^liot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



PTYCHOPARIA TOLUS, new species. 



Of this species only a single fragmentary head is known; this is 

 much like the corresponding parts of the head of Ptychoparla Liostra- 

 cvs tliraM).^ but it differs {a) in being less convex, {J)) in having a more 

 coarsely granulated surface, (c) stronger posterior glabellar furrows, 



