2l8 RESEARCH IN CHINA. 



Dolichometopus dirce Walcott. 



Plate 22, Figures 5, 5<i-i. 

 !>nln /iiniietopiis dirce WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxix, p. 96. (Characterized as a new 



species as below.) 



Only the central portions of the cephalon of this species are known. It differs 

 from D. deois [plate 22, fig. i] in the nearly parallel sides of the glabella, the absence 

 of glabellar furrows, and the very short, almost flat, frontal limb. The occipital 

 lobe is nearly one-half the length of the cephalon. 

 Surface under strong magnifier smooth. 

 The type specimen of the cephalon has a length of 1 1 mm. 

 Formation and Locality. Middle Cambrian: (C24) Near top of black oolite 

 group in the uppermost layers of the Ch'ang-hia formation [Blackwelder, 19070, p. 

 33 (part of last list of fossils)], 2 miles (3.2 km.) east of Ch'ang-hia, Shan-tung, China. 

 Collected by Eliot Blackwelder. 



Dolichometopus hyrie Walcott. 



Plate 22, Figures 6, 6a-b. 



Dolichomelopus hyrie WALCOTT, 1906, Proc. U. S. Nat. Mus., vol. xxx, p. 594. (Described and dis- 

 cussed as a new species essentially as below.) 



This species is represented by a single specimen of the central portions of the 

 cephalon, and an associated free cheek and pygidium. Glabella moderately convex, 

 with the sides slightly converging toward the broadly rounded front; glabellar 

 furrows faintly impressed; the posterior pair extends obliquely inward and back- 

 ward, obscurely outlining a subtriangular lobe on each side; also two pairs of short, 

 faintly impressed furrows extend in at nearly right angles to the sides of the gla- 

 bella; occipital furrow shallow, somewhat deeper at the sides than in the center; 

 occipital ring narrow at the sides, widening gradually toward the center, where it is 

 of medium width, slightly convex, and rising but little above the general surface 

 of the glabella; dorsal furrow shallow, indicated by the union of the sloping sides 

 and front of the glabella with the fixed cheeks and frontal limb. 



Fixed cheeks narrow, nearly flat opposite the palpebral lobes, and sloping gently 

 to the front and back ; what is preserved of the palpebral lobes indicates that they 

 were elongate, extending about one-third or more of the length of the cephalon; a 

 narrow, slightly elevated palpebral ridge extends obliquely across the narrow fixed 

 cheek ; frontal rim short and nearly flat ; the curved angle at the union of the fixed 

 cheeks and glabella gives the impression that the frontal rim is slightly concave. 



The associated free cheek is shown in figure 6a. 



Surface, as seen by a strong lens, slightly roughened with minute granules. 

 The type and only specimen in the collection has a length of 7.5 mm. 



The associated pygidium is transverse, semicircular, and convex; axial lobe 

 convex, a little more than three-fourths the length of the pygidium, and crossed by 

 three rather clearly defined, narrow furrows, which differentiate three rings and a 

 terminal portion ; the outline of the axis is continued by a low swelling that extends 

 from the end of the convex axis to the posterior margin; the furrows crossing the 

 axis curve outward and slightly backward across the pleural lobes to the margin of 

 the border ; they are broader than the furrows on the axis and separate three rather 

 clearly defined segments from a narrow frontal rim and a posterior portion back of 

 the axis; border relatively narrow and sloping gently from the base of the pleural 

 lobe to the outer margin; it arches slightly inward back of the axis. The largest 

 specimen has a width of 26 mm., with a length of 14 mm. A small specimen 15 mm. 

 in width has a less clearly defined border, and in other respects resembles the pygid- 

 ium associated with I'), d co-is [plate 22, fig. ij. 



