IJ2 RESEARCH IN CHINA. 



the strong rounded rim; the front of the glabella passes into the broad groove that 

 merges into the upward-sloping, narrow frontal limb; frontal rim rounded and 

 marked by rather strong striae parallel to the frontal border. 



Surface smooth to the unaided eye ; a strong lens shows a slight, irregular pitting 

 where the outer surface is intact. The type specimen of the cephalon has a length 

 of 20 mm. 



This species was at first confused with Chuangia batia. It differs from the 

 latter in the form of the glabella and the size of the palpebral lobes and frontal limb. 

 The same features distinguish it from Chuangia nitida and C. fragmenta. 



Formation and Locality. Upper Cambrian: (C64) Upper limestone member 

 of the Kiu-lung group [Blackwelder, 19070, pp. 37 and 42 (first list of fossils), and 

 fig. 10 (bed 20), p. 38], 2.7 miles (4.3 km.) southwest of Yen-chuang, Sin-t'ai district, 

 Shan-tung, China. 



Collected by Eliot Blackwelder. 



Chuangia nitida Walcott. 

 Plate 17, Figure 21. 



Chuangia nitida WALCOTT, 1911, Smithsonian Misc. Coll., vol. 57, No. 4, pp. 85-86, plate 15, fig. 6. 

 (Described and discussed as a new species essentially as below.) 



Only the central portions of the moderately convex cephalon are known of 

 this species. Within the facial sutures the outline is subquadrangular, exclusive 

 of the short postero-lateral limb. Glabella slightly convex, truncato-conical, with 

 a very slight trace of short, slightly oblique posterior glabellar furrows; the latter 

 are shown more distinctly on the cast of the interior ; occipital furrow shallow and 

 clearly defined ; occipital ring slightly convex and rather broad toward the center ; 

 dorsal furrow shallow at the sides of the glabella. 



Fixed cheeks about one-half the width of the glabella, gently convex ; palpebral 

 ridges strong, low, and passing obliquely backward to the rim of a rather large 

 palpebral lobe ; the latter is a little longer than one-third the length of the cephalon. 

 The frontal limb is represented by the short concave space in front of the glabella, 

 which forms a sharp angle in uniting with the frontal limb. 



Surface slightly pitted when seen through a strong magnifying glass. Length 

 of cephalon, 7 mm. 



This species is much smaller than the type species, Chuangia batia [p. 170]. It 

 differs from the latter in its narrower frontal limb, larger palpebral lobes, and more 

 elongate glabella. From Chuangia nais and C. fragmenta [p. 171] it differs in its 

 longer palpebral lobes and outline of the glabella. 



Formation and Locality. Upper Cambrian : (Cll) Crystalline limestone 60 feet 

 (18 m.) above the base of the uppermost limestone member [Blackwelder, 1907(7, 

 pp. 37 and 41 (last list of fossils)], 2.1 miles (3.4 km.) southwest of Yen-chuang, Sin- 

 t'ai district, Shan-tung, China. 



Collected by Eliot Blackwelder. 



Genus MENOCEPHALUS Owen. 



Menoceplmlus OWEN, 1852, Geol. Surv. Wisconsin, Iowa, and Minnesota, p. 577, plate i, fig. n. 



Doctor Owen proposed this genus for trilobites having a highly convex, hemi- 

 sperical glabella, with a narrow border and a broadly rounded front; cheeks tumid, 

 surface pustulate. 



The genotype of Menocephalus was destroyed by fire many years ago. A 

 careful study of a large collection of specimens from the type locality at Minneiska in 



