140 RESEARCH IN CHINA. 



Surface smooth to the unaided eye, finely punctate under a strong lens. The 

 largest cephalon referred to this species has a length of 9 mm., and the specimen 

 selected as the type a length of 4 mm., with a width at the outer edge of the palpe- 

 bral lobes of 6 mm. 



The associated free cheek has the same type of nearly flat rim as the rim in 

 front of the glabella; this is extended at the postero-lateral angle into a moder- 

 ately strong, sharp spine; the body of the cheek rises to the base of the eye-lobe with 

 very little convexity; it is separated from the lateral and posterior borders by a 

 shallow furrow; the surface is marked by irregular lines radiating from the base of 

 the eye-lobe toward the furrow within the outer margin. 



The associated pygidium has a planulate border that merges into the slope of 

 the pleural lobes; axis convex, about three-fourths the length of the pygidium, and 

 marked by three shallow, transverse furrows that are continued across the pleural 

 lobes out onto the planulate margin. 



The general form of the cephalon of this species is much like that of Ptychoparia 

 impar [p. 131]. It differs in having a flatter frontal rim, less convex frontal limb, 

 stronger glabellar furrows, and larger palpebral lobes. From Anomocare megalurus 

 Dames [p. 192] it differs by having a more subquadrangular glabella and larger palpe- 

 bral lobes. 



Formation and Locality. Middle Cambrian: (CG9) Limestone in shales about 

 65 feet (19.5 m.) above the base of the Ki-chou limestone [Willis and Blackwelder, 

 1907, p. 145 (first list of fossils)], 4 miles (6.4 km.) east of Fang-lan-chon, Shan-si, 

 China. 



Collected by Eliot Blackwelder. 



Conokephalina sp. undt. (Walcott). 

 Plate 13, Figure 10. 



Ptychoparia sp. undt. WALCOTT, 1906, Proc. U. S. Nat. Mus., vol. xxx, p. 591. (Species discussed 

 essentially as below.) 



This form is represented by a minute cephalon 1.25 mm. in length. It has an 

 elongate glabella of the type of Ptychoparia (Emmrichelld) theano [p. 136] but its 

 palpebral lobes are longer than in that species. It may be the young of Conokeph- 

 alina maia, which occurs at the same locality but not in the same layer of rock. 



A small cephalon about 2 mm. in length of about the same character as the one 

 mentioned above, but differing from it in having a shorter frontal limb, occurs (C72) 

 in the upper portion of the Ki-chou limestone, 4 miles (6.4km.) east of Fang-lan-chon, 

 Shan-si, China. The locality of the cephalon first described is as follows: 



Formation and Locality. Middle Cambrian : (C 70) Oolitic limestone about 30 

 feet (9 m.) above the base of the Ki-chou limestone [Willis and Blackwelder, 1907, 

 p. 144 (last list of fossils)], 4 miles (6.4 km.) south-southwest of Tung-yii, Shan-si, 

 China. 



Collected by Eliot Blackwelder. 



Genus CREPICEPHALUS Owen. 



Crepicephalus convexus Walcott. 



Plate 13, Figures 16, i6a-b. 



Crepicephalus convexus WALCOTT, 1911, Smithsonian Misc. Coll., vol. 57, No. 4, pp. 79-80, plate 14, 

 figs. 1 1 and i ia. (Described and discussed as a new species essentially as below.) 



The cranidium of this species differs from that of C. damia Walcott in its 

 shorter frontal lobe, flatter frontal rim, and proportionately longer glabella. The 



