NO. 5 CAMBRIAN TRILOBITES 367 



kia-p'u, and 4 miles (6.4 km.) north of Sin-t'ai-hien, Sin-t'ai district, 

 Shan-tung, China. 



Also from localities: (35 o) Fu-chou series, shales about 130 feet 

 (40 m.) above the white qtiartzite * collected in drainage cuts a short 

 distance back from the bluff forming the shore of Tschang-hsing-tau 

 Island; (35p) shales about 80 feet (24 m.) above the white quartz- 

 ite," and (ssr) limestones near the base of the series just above the 

 white quartzite,^ the latter two collected in a low bluff on the shore 

 of Tschang-hsing-tau Island, east of Niang-niang-kung, Liau-tung, 

 Manchuria, China. 



DOLICHOMETOPUS (?) DERCETO Walcott 



Plate 54, figs. 4, 4a 



Dolichomctopiis dcrceto Walcott, 1905, Proc. U. S. Nat. Mus., Vol. 29, p. 95. 



(Described as a new species as below.) 

 Dolichometopus derccto Walcott, 1913, Research in China, Vol. 3, p. 217, 



pi. 22, figs. 4, 4a. (Described and illustrated.) 



This species is known only by the central portions of the cephalon, 

 exclusive of the free cheeks. Glabella moderately convex and 

 expanding slightly in width from the base to the rounded front ; the 

 surface is marked by two pairs of rather strong, short furrows 

 opposite the palpebral lobe ; occipital furrow strong and rather deep ; 

 occipital ring narrow at the sides, rising and widening to forin the 

 base for a small, sharp occipital spine ; dorsal furrow strong on the 

 sides of the glabella. ^ 



Fixed cheeks narrow, convex ; palpebral lobe narrow, elongate, 

 almost touching the dorsal furrow in front ; postero-lateral limb of 

 medium length, marked by a strong furrow parallel to the posterior 

 margin ; frontal limb narrow, slightly concave, and almost concealed 

 by the overhanging, almost tumid frontal portion of the glabella. 



Surface smooth under a strong lens. 



The largest of the three cephala representing this species has a 

 length of 7 mm., exclusive of the occipital spine. 



Formation and locality. — Middle Cambrian: (Ci and C2) Lower 

 shale of the Kiu-lung group,^ 2 miles (3.2 km.) south of Yen-chuang, 

 Sin-t'ai district, Shan-tung, China. 



^ Blackwelder, Research in China, Pub. No. 54, Carnegie Inst, of Washington, 

 Vol. I, Pt. I, 1907, p. 92, for general section giving stratigraphic relations. 



^ Idem, pp. Z7 ^-^^ 40 (part of the third list of fossils), and fig. 10 (beds 4 

 and 5), p. 38. 



