368 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 64 



DOLICHOMETOPUS (?) DIRCE Walcott 



Plate 54, figs. 5, sa-b 



Dolichometopus dirce Walcott, 1905, Proc. U. S. Nat. Museum, Vol. 29, 



p. 96. (Characterized as a new species as below.) 

 Dolichometopus dirce Walcott, 1913, Research in China, Vol. 3, p. 218, pi. 



22, figs. 5, sa-b. (Described and illustrated.) 



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

 It differs from D. {?) deois (pi. 54, 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 forma- 

 tion,* 2 miles (3.2 km.) east of Ch'ang-hia, Shan-tung, China. 



DOLICHOMETOPUS ? EXPANSUS (Walcott) 

 Plate 53, figs. 5, 5a 



Dicellocephalus ? expansus Walcott, 1884, Monogr. U. S. Geol. Survey, 

 Vol. 8, p. 45, pi. 9, fig. 19. (Description and illustration of cranidium.) 



Dicellocephalus ? quadriceps Hall and Whitfield, Walcott, 1884, Monogr. 

 U. S. Geol. Surv., Vol. 8, p. 45, pi. 9, fig- 24. (Describes occurrence 

 oi species and illustrates a cranidium distorted by longitudinal com- 

 pression.) 



Dicellocephalus (?) expansus Matthew, 1893, Trans. Royal Soc. Canada, 

 Vol. 10, Sec. 4, p. II, footnote. (Considers generic reference as doubt- 

 ful.) 



Dolichometopus expansus (Walcott), 1914, Smithsonian Misc. Coll., Vol. 

 57. P- 350. (Change of generic reference of species.) 



Original description^' — Glabella elongate subquadrangular or sub- 

 clavate, the base about one-fifth narrower than the front ; surface 

 convex and without perceptible furrows ; occipital furrow distinctly 

 defined ; occipital ring strong with a small spine on the center of the 

 posterior portion ; dorsal furrows well defined along the sides of the 

 glabella ; fixed cheeks of medium width, palpebral lobes unknown ; 

 an ocular ( ?) ridge crosses the anterior portion of the right fixed 

 cheek so as to indicate a moderate sized eye lobe between it and the 

 postero-lateral limb; frontal limb as a narrow rim; postero-lateral 



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

 ton, Vol. I, Pt. I, 1907, p. S3 (part of last list of fossils). 



" Walcott, Monographs U. S. Geological Survey, Vol. 8, 1884, pp. 45-46- 



