CAMBRIAN FAUNAS OF CHINA— WALVOTT. 589 



median ridge; occipital furrow shallow but clearly defined; occipital 

 ring nearly flat, sloping from the shallow furrow slightly upward to 

 the posterior margin, it narrows at the sides to two-thirds of its width 

 at the center; dorsal furrow narrow, shallow, and clearly defined at the 

 sides of the glabella, in front it is little more than the angle formed by 

 the union of the glabella and frontal liml). 



Fixed cheeks narrow, about one-third the width of the glabella, 

 slightly conyex opposite the palpebral lobes, and merging into the 

 frontal limb in front of the ocular ridges, and sloping more gently 

 backward to the posterior furrow; palpebral lobes narrow, about one- 

 third the length of the head, and separated from the fixed cheeks by 

 shallow furrows; postero-lateral limb short, and marked by a rather 

 broad, shallow posterior furrow within a yery narrow posterior mar- 

 gin; frontal limb short, sloping down to the yery narrow, slightly 

 defined furrow that separates it from the nearly flat, narrow frontal 

 rim. 



Surface slightly roughened, but from its condition it is impossible 

 to state whether it is like the surface of Pfi/cJioparia I'llla (p. 588). The 

 largest head in the collection has a length of 3.5 mm. 



ObservatloiDi. — The subrectangular glabella is somewhat like that 

 of PtycJioparia acJls: Walcott,-' but the short frontal limb and flat rim 

 distinguish it from the latter species. 



It is associated with Ptychojjaria vesta (p. 590), from which it differs 

 in the form of the glabella and palpebral lobes. 



A form closely related to this occurs about 100 feet lower at the 

 same locality and section. 



formation (Oid localiti/. — Middle Cambrian, lower portion of oolitic 

 limestone series; 4 miles east of Fang-lan-chon, Shan-si, China. 



Collected by Eliot Blackwelder. 



PTYCHOPARIA UNDATA, new species. 



This species is represented by four specimens of the central portions 

 of the head, exclusiye of the free cheeks. These show that the head 

 was semicircidar in outline and rather strongly conyex. Glabella 

 conyex, irregularly subquadrangular in outline, it narrows slightly 

 from the base toward the front; the postero-lateral angles are rounded, 

 and the anterior angles more broadly rounded into the slightly curyed 

 front; three pairs of glabellar furrows are indicated by slight depres- 

 sions that extend in from the margin about one-half the distance to 

 the median line; the posterior pair extends obliquely backward so as 

 to indicate oyal postero-lateral lobes; occipital ring rounded and 

 strongly deflned, narrow at the sides, gradually widening toward the 

 center, which is slightly aboye the plane of the surface of the glabella; 

 occipital furrow narrow, rounded, distinct, and curving slightly for- 



«Proc. U. S. Nat. Mus., XXIX, 1905, p. 75. 



