586 \ PROCEEDINGS OF THE NATIONAL MUSEUM. 



Fixed cheeks narrow iiii<l rising abruptly from the dorsal furrow, 

 nearly flat opposite the palpebral lobes; they slope abruptly down- 

 ward toward the posterior furrow and toward the frontal rim; palpe- 

 l)i'al lobes narrow, rounded, and separated from the fixed cheeks by 

 strong, narrow furrows; frontal rim convex, prominent, and separated 

 from theghibella l>y the deep dorsal furrow, and from the fixed cheeks 

 by a narrow, deep furrow that extends obliquely outward and forward 

 from opposite each antero-lateral angle of the glabella. 



The surface of tlie glabella is marked b}' raised, irregular, more or 

 less inosculating, sharp ridges, the general direction of which is trans- 

 verse to the axis of the glabella; the fixed cheeks are marked liy ridges 

 somewhat like those on the glabella, which are sul)parallel to the dor- 

 sal furrow and the furrow within the palpebral lobes; the ridges on 

 the frontal liml) are broken up into large granulations by the inoscu- 

 lating furrows. A head 11 mm. in length has a width of 12 mm. at 

 the palpebral lobes. 



Observation,^. — The general form of the central parts of the head of 

 this species suggests Pfi/('Ji((spls acanuis Walcott.** It differs from the 

 latter in the form of the glabella in front of the transverse glabellar 

 furrow, the elevated lines on the fixed cheeks instead of granulations, 

 and in minor details of the occipital and glabellar furrows. 



Formation and locality. — Upper Cambrian, blue, doloraitic lime- 

 stone, probably equivalent to the Ch'au-mi-tien limestone of Shan- 

 tung; tt miles east of Fang-lan-chon, Shan-si, China. 



Collected h\ Eliot Blackwelder. 



Genus PTYCHOPARIA Hawle and Corda. 

 PTYCHOPARIA COMUS, new species. 



Of this species only the central portions of two small heads are 

 known. The glal)ella and fixed cheeks are convex; glabella convex, 

 truncato-conical, and marki^l by three pairs of faint furrows; occipital 

 furrow rather l)road, rounded, and moderately deep; occipital ring 

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

 a little elevated above the plane of the glabella and not much wider 

 than the occipital furrow; dorsal furrow clearly defined on the sides 

 and slightly marked in front of the glabella. 



Fixed cheeks narrow, not over one-fourth the width of the glabella; 

 palpebral l;)l)es about one-third the length of the head, somewhat 

 nearer the posterior than the frontal margin of the head; ocular ridge 

 short, and not prominent, it terminates a little l»ack of the antero- 

 lateral angle of the glabella; frontal limb narrow, very slightl}' con- 

 vex, and sloping downward with a well defined furrow separating it 

 from the strong, rounded, thickened frontal rim; four small, shallow 



aProc. U. S. Nat. Mus., XXIX, 1905, p. 69. 



