176 RESEARCH IN CHINA. 



Menocephalus agave Walcott. 

 Plate 1 6, Figure 9. 



Moioccphaliis agave WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxix, p. 62. (Characterized as a new 

 species as below.) 



Another species of Menocephalus is associated with Levisia adrastia [p. 17 7], in 

 which only the anterior portions of the cephalon and one fixed cheek are preserved. 

 This differs from L. adrastia in the proportionately narrower glabella, rounded 

 frontal rim, and less convex fixed cheek. Its surface is very finely pustulose, with 

 scattered larger pustules on the glabella. The palpebral lobe is very small and 

 situated a little back of the center of the cephalon. 



Formation and Locality. Middle Cambrian : (C30) Layer in black oolite of the 

 Ch'ang-hia limestone [Blackwelder, 19070, p. 33 (part of first list of fossils)], 25 

 feet (7.5 m.) above the second cliff at an elevation of 1,700 feet (568.9 m.) on top of 

 the long north and south ridge at Ch'ang-hia, Shan-tung, China. 



Collected by Eliot Blackwelder. 



Menocephalus ? depressus Walcott. 

 Plate 1 6, Figures 6, 6a. 



Menocephalus ? depressus WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxix, p. 62. (Described as a 

 new species as below.) 



General form of the cephalon, exclusive of the free cheeks, subrhomboidal, 

 moderately convex. Glabella moderately convex, narrowing slightly from the base 

 toward the rather broadly rounded front; surface marked by two pairs of very 

 shallow, short glabellar furrows; occipital furrow narrow, transverse, and sharply 

 impressed ; occipital ring slightly convex and of nearly uniform width ; dorsal furrow 

 narrow and sharply defined. 



Fixed cheeks about one-half the width of the glabella, convex, arching with 

 about the same slope to the palpebral lobe from the front and back ; palpebral lobe 

 small, situated about midway of the cheek ; no evidence of the presence of a palpe- 

 bral ridge; postero-lateral limb short, marked by a distinct groove parallel to the 

 narrow, elevated posterior margin ; frontal rim narrow, convex, and separated from 

 the glabella and fixed cheeks by a distinct, narrow groove. 



Surface with numerous low, medium-sized, scattered pustules. 



The type and only specimen of the cephalon in the collection has a length of 

 4.5 mm. 



This species is doubtfully referred to the genus Menocephalus. It is most 

 nearly related to M. acis, but differs in having a less convex glabella and narrower 

 fixed cheeks. 



Formation and Locality. Upper Cambrian: (C56) Lower part of Ch'au-mi- 

 tien limestone, 25 feet (7.5 m.) below the top of Pagoda Hill [Blackwelder, 19070, 

 p. 42 (part of last list of fossils)], i mile (1.6 km.) west of Tsi-nan, Shan-tung, and 

 (C49), purplish-brown limestone in the lower part of the Ch'au-mi-tien limestone 

 [idem, p. 36 (part of first list of fossils)], in roadway 2.5 miles (4km.) west-southwest 

 of Ch'au-mi-tien, Shan-tung, China. 



Collected by Eliot Blackwelder and Li San. 



Menocephalus ? sp. undt. Walcott. 

 Plate 16, Figures 7, 70. 



Menocephalus sp. undt. WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxix, p. 63. (Species described 



as below.) 



This form is represented by the anterior half of the glabella and fixed cheeks. 

 These parts indicate that the glabella was strongly convex, rounded in front, and 



