158 RESEARCH IN CHINA. 



Agraulos nitida Walcott. 

 Plate 15, Figures 2, 2a-b. 



Agraulos nitida WALCOTT, 1906, Proc. U. S. Nat. Mus., vol. xxx, p. 576. (Described as a new species 

 essentially as below.) 



This species is represented by the central portions of the cephalon, exclusive 

 of the free cheeks; the front within the facial sutures is strongly rounded, indicating 

 a semicircular outline for the cephalon, which was moderately convex. Glabella 

 truncato-conical, moderately convex, and not very clearly defined from the fixed 

 cheeks and frontal limb ; there are no traces of glabellar furrows ; occipital furrow 

 represented by a slight depression at the base of the glabella; occipital ring very 

 narrow at the sides, thickening rapidly toward the center so as to give it a subtri- 

 angular outline, the apex of which terminates in a small spine of 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 posterior furrow, and to 

 the front to merge into the frontal limb, which is slightly convex; palpebral lobes 

 about one-fourth the length of the cephalon. 



Surface slightly roughened by what appears to be a minutely granulated surface 

 as shown by a strong lens. 



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



This species is most nearly related to Agraulos dolon [p. 156]. The cephalon 

 of the latter differs in being longer in proportion to the width, and in having broader 

 fixed cheeks. 



Formation and Locality. Middle Cambrian: (C75) Limestone near the base 

 of the Ki-chou formation [Willis and Blackwelder, 1907, p. 143], 4.5 miles (7.2 km.) 

 south of Wu-t'ai-hien, Shan-si, China. 



Collected by Eliot Blackwelder. 



Agraulos obscura Walcott. 



Plate 15, Figure 4. 

 Agraulos obscura WAUCOTT, 1906, Proc. U.S. Nat. Mus., vol. xxx, p. 577. (Described as a new species.) 



This species is represented by the central portions of the cephalon, exclusive 

 of the free cheeks. The glabella and fixed cheeks moderately convex; glabella 

 truncato-conical, with the front margin gently 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 interruption by 

 the occipital furrow; surface of glabella smooth, with the exception of some very 

 slight indications of a posterior pair of furrows; occipital furrow shallow, and 

 fading 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 furrow of medium width and well defined at the sides and front 

 of the glabella. 



Fixed cheeks narrow, convex, rising into narrow ridges that anteriorly form 

 a node or swelling where they merge into the frontal limb ; posteriorly they slope 

 down to merge with the postero-lateral limb ; palpebral lobes small, somewhat 

 elevated, and separated from the fixed cheeks by a shallow furrow; there does not 

 appear to be any palpebral 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 



