DESCRIPTION OF GENERA AND SPECIES. 209 



Anomocarella trogus (Walcott). 

 Plate 19, Figure u. 



Plyiiioparia (Liostracus) trogus WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxix, p. 83. (Species 

 described as below.) 



Cephalon small, transversely quadrilateral, exclusive of the free cheeks, moder- 

 ately convex. Glabella broadly truncato-conical and without traces of glabellar 

 furrows ; occipital furrow narrow and rather shallow, rising on the back to the rather 

 strong, rounded occipital ring; the latter is broad through the central portions, 

 narrowing at the sides; dorsal furrow rounded and well defined. 



Fixed cheeks about one-half the width of the glabella; palpebral lobes small; 

 palpebral ridges very faint ; frontal limb very narrow, in fact it is difficult to decide 

 that the dorsal furrow does not unite with a depressed space in front of the glabella 

 that merges into the frontal furrow; the latter is rounded, shallow, and defines the 

 strong, slightly convex frontal rim; postero-lateral limbs short, marked with a very 

 distinct transverse furrow just within the posterior margin. 



vSurface apparently smooth under a strong lens. 



This species differs from other forms in the very short frontal limb and flattened 

 frontal rim. 



Formation and Locality. Middle Cambrian: (C25) Limestone about 50 feet 

 (15 m.) below the Ku-shan shale in the uppermost beds of the Ch'ang-hia formation 

 [Blackwelder, igoja, p. 33 (part of the last list of fossils)], at Ch'ang-hia, Shan-tung, 

 China. 



Collected by Eliot Blackwelder. 



Anomocarella tutia (Walcott). 

 Plate 19, Figure 15. 



Ptychopariu (Liostracus) liitia WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxix, p. 84. (Species 

 described essentially as below.) 



The cephalon is small, strongly convex. Glabella very convex, almost tumid; 

 truncato-conical in outline, and without traces of glabellar furrows; occipital furrow 

 narrow ; occipital ring strong and narrow at the sides, none of the specimens show it 

 entire at the center ; dorsal furrow narrow and rather deep on the sides of the glabella, 

 not distinctly defined in front. 



Fixed cheeks about two-thirds of the width of the glabella; palpebral lobes 

 small, with their posterior end on a line with the longitudinal center of the cephalon ; 

 palpebral ridges narrow but very clearly defined; frontal limb gently convex, rather 

 short, and very indistinctly separated from the rather broad, almost flattened 

 frontal rim ; postero-lateral limbs strong but short ; marked by a strong transverse 

 furrow just within the posterior margin. 



Surface minutely granulose. 



The largest cephalon in the collection has a length of 4 mm. 



This very pretty little cephalon is of the general type of Ptychoparia ? talus 

 [plate 12, fig. 13] but it differs in the greater convexity of the glabella and the form 

 of the frontal limb. 



Formation and Locality. Middle Cambrian: (C'12) Gray limestone near the 

 top of the middle limestone member of the Kiu-lung group [Blackwelder, 19070, pp. 

 37 and 41 (part of the first list), and fig. 10 (bed 7), p. 38] 3.25 miles (5.2 km.) 

 southwest of Yen-chuang, Sin-t'ai district, Shan-tung; also (C19), uppermost layers 

 of the Ch'ang-hia limestone [idem, p. 33 (part of last list of fossils)], at Ch'ang-hia, 

 Shan-tung, China. 



Collected by Eliot Blackwelder and Li San. 



