'^"''- CAMBBIAN FAUNAS OF CHINA-WALCOTT. 577 



very narrow at the sides, thickening rapidly toward the center so as to 

 give It a subtriangular outline, the apex of which terminates in a small 

 spme ot unknown length; dorsal furrow indicated by the difference in 

 slope of the glabella and fixed cheeks and frontal limb 



Fixed cheeks less than one-half the width of the glabella, nearly flat 

 opposite the palpebral lobes, and sloping gently downward to the pos- 

 terior furrow, and to the front to merge into the frontal limb, which is 

 slightly convex; palpebral lobes about one-fourth the leno-th of the 

 head. * 



Surface slightly roughened by what appears to be a minutelv gran- 

 ulated surface as shown by a strong lens. 



The largest head in the collection has a length of .5 mm 

 wTTfZT'T^^f species is most nearly related to Ai.raulos dolon 

 Wa cott.« The head of the latter differs in being longer in proportion 

 to the width, and in having broader fixed cheeks. 



Formation and /'^>m^%. -Middle Cambrian, in brownish-crra^' oolitic 

 imestone, 10 feet above red shales of supposed Man-t'o f oniiati'on age: 

 4.5 miles south of Wu-t'ai-hie'n, Shan-si, China. 



Collected by Eliot Blackwelder. 



AGRAULOS OBSCURA, new species. 



This species is represented by the central portions of the head 

 exclusive of the free cheeks. The glabella and fixed cheeks moder- 

 ately convex; glabella truncato-conical, with the front margin gentlv 

 curved, and antero-lateral angles slightly rounded; the postero-lateral 

 angles are more broadly rounded and pass into the line of the posterior 

 margin of the occipital ring without intei-ruption by the occipital fur- 

 row; surface of glabella smooth, with the exception of some very 

 slight indications of a posterior pair of furrows; occipital furrow shal- 

 low, and dying out before reaching the dorsal furrow; occipital ring 

 narrow at the ends, broadening and rising toward the center to form 

 the base of what may be a short spine, or a slight upward projection 

 of the central portion of the posterior margin of the ring; dorsal fur- 

 row of medium width and well defined at the sides and front of the 

 glabella. 



_ Fixexl cheeks narrow, convex, rising into narrow ridges that ante- 

 riorly form a node or swelling where they merge into the frontal limb 

 posteriorly they slope down to merge with the postero-lateral liml)- 

 palpebral lobes small, somewhat elevated, and separated from the 

 fixed cheeks by a shallow furrow; there does not appear to be any 

 ocular ridge; postero-lateral limb about as long as the width of the 

 glabella in front; it is marked by a shallow furrow within the slightly 

 rounded posterior margin; frontal limb and rim in front of the 



«Proc. IT. S. Nat. Mus., XXIX, 1905, p. 45. 

 Proc. N. M. vol. XXX— 06 37 



