DESCRIPTION OF GENERA AND SPECIES. 169 



Solenopleura intermedia (Walcott). 

 Plate 17, Figures 16, i6a. 



Ptychoparia (Liostracus) intermedia WALCOTT, 1906, Proc. U.S.Nat. Mus.,vol. xxx, p. 592. (Species 

 compared with other species of Ptychoparia and subgenus Liustracus.) 



This species is represented by a single well-preserved specimen of the central 

 portions of the cephalon. It differs in details from S. agno [plate 17, fig. 15,] and 

 S. beroe [plate 17, figs. 14, 140, 17], as may be seen by comparing the figures. 



The surface of 5. intermedia is marked by a few scattered, rather large tubercles 

 and many very fine tubercles. A cephalon 8 mm. in length has a width at the 

 outer edge of the palpebral lobes of 9 mm., with a convexity of 2 mm. above the 

 plane of the margin of the cephalon. 



Formation and Locality. Middle Cambrian: (C51) Lower part of gray crys- 

 talline limestone in the upper portion of the oolitic part of the Ch'ang-hia limestone 

 [Blackwelder, 19070, p. 33 (part of the first list of fossils)], at Ch'au-mi-tien, Shan- 

 tung, China. 



Collected by Eliot Blackwelder. 



Solenopleura pauperata Walcott. 



Plate 17, Figure 18. 



Solenopleura pauperata WALCOTT, 1906, Proc. U. S. Nat. Mus., vol. xxx, p. 593. (Described as a new- 

 species essentially as below.) 



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

 of the free cheeks and the occipital ring. The portions preserved show that the 

 cephalon was semicircular and rather strongly convex. Glabella truncato-conical, 

 rounded in front, strongly convex, and marked by three pairs of very short, slightly 

 impressed furrows ; the fragment of the occipital furrow remaining shows it to have 

 been narrow and rather deep; occipital ring unknown; dorsal furrow narrow and 

 rather deep at the sides, and clearly defined in front of the glabella. 



Fixed cheeks about two-thirds the width of the glabella, convex, and curving 

 gently to the front and back ; palpebral lobes central and small ; no traces of palpe- 

 bral ridges; postero-lateral limb about as long as the width of the glabella, and 

 marked by a sharply impressed furrow within a narrow, rounded posterior rim; 

 the line of demarcation between the front of the glabella and the frontal rim is a 

 rather deep, narrow furrow, no traces of a frontal limb being present ; frontal rim 

 strong, rounded, and broadly curved in front. 



Surface minutely granular, with a few larger granules scattered over the surface 

 of the glabella, and a number of slightly larger granules scattered over the surface 

 of the fixed cheeks. The type and only specimen of the cephalon has a length of 

 3 mm., exclusive of the occipital ring. 



This species is characterized by the absence of a frontal limb, and its broadly 

 conical glabella, in these respects differing from Solenopleura agno [plate 17, fig. 15] 

 and S. beroe [plate 17, fig. 14]. It also differs from the two mentioned species by 

 having a more finely granulated surface. 



Formation and Locality. Middle Cambrian: (C71) Massive cliff-making lime- 

 stone in the central portion of the Ki-chou formation [Willis and Blackwelder, 1907, 

 pp. 139 and 145 (second list of fossils)], 4 miles (6.4 km.) southwest of Tung-yii, 

 Shan-si, China. 



Collected by Bailey Willis and Eliot Blackwelder. 



