88 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxix. 



furrow; the latter is formed of two slightly forward arching, nar- 

 row furrows in front of the fixed cheeks, that merge into a very 

 shallow furrow in front of the glabella; the central portion of the 

 furrow arches slightly backward; the furrows are deepest opposite 

 the antero-lateral angles of the glabella; frontal rim sub-triangular 

 in outline, nearly flat, and extending forward at the center to form 

 the base of a long, slender, rounded spine. 



Surface minutely punctate under a strong lens. A head 7 nmi. in 

 length, exclusive of the frontal spine, has a width of 9 mm. at the outer 

 margin of the palpebral lobes; the glabella is 2.5 mm. at the base, and 

 with the occipital ring is 5 mm. in length, the flat frontal rim and spine 

 of a head of about the same size has a length of alwut 8 mm., the 

 spine, at the point where broken off, having a width of 1 mm. 



I do not know of any other form closeh^ related to this species. 

 Prowmpyx acimiinatwm Angelin has a similar nasute projection on the 

 frontal rim, but it differs in the form of the glabella and palpebral 

 lobes and other details of the head. The same is true of the species 

 described as Ptychoparia j)ernasutus Walcott.'' 



Formation and locality. — Middle Cambrian, Ku San shale forma- 

 tion; 2.5 miles southwest of Yen Chuang, HsinTai, Shangtung, China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



Genus SOLENOPLEURA Angelin. 

 SOLENOPLEURA ABDERUS, new species. 



This species is represented by the glabella, occipital ring, fixed cheek, 

 and frontal rim. It is most closely related to S. acantJta, ])ut differs 

 in the narrower fixed cheeks, and short, rounded, frontal rim. The 

 surface is also marked by larger and many more pustules, which are 

 scattered more or less irregularly over the surface. Three pairs of 

 short glabellar furrows are fainth^ indicated upon the rounded sides of 

 the somewhat convex glabella. The type specimen has a length of 8 

 mm., and a larger head associated with it of 12.5 mm. 



Formation and locality. — Middle Cambrian, upper portion of the 

 Chang Hsia formation, just beneath the Ku San shale, in a gray, rather 

 coarse limestone; Chang Hsia, Shangtung, China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



SOLENOPLEURA ACANTHA, new species. 



General form of head, exclusive of free cheeks, transversely rhom- 

 boidal and rather convex. Glabella prominent, convex, truncato- 

 conical, with width at the base and length about the same; a short, 



aMon. U. S. Geol. Survey, VIII, 1884, p. 49, pi. x, fig. 8. 



