NO. 1415. CAMBRIAN FAUNAS OF CHINA— WALCOTT. 85 



PTYCHOPARIA (LIOSTRACUS) THRASO, new species. 



Head subquadrilateral in outline, exclusive of the free cheeks; 

 stronoly convex; g-Uibella prominent, convex, sides straight, and con- 

 verging toward the front from a width of 6 mm. at the base to 4 mm. 

 at the front in a glabella 0.5 mm. long; front arched, and with a pit 

 in the furrow where the sides and front unite; three shallow broad 

 furrows extend nearly to the center from each side, so as to divide 

 the surface into two narrow lobes — a terminal lobe and a strong- pos- 

 terior lobe; occipital furrow strong and arching forward at the center; 

 occipital ring narrow at the sides and gradually increasing in width to 

 the center; dor.sal furrow narrow and well defined. Fixed cheeks 

 narrow; palpebral lobes central, and small; posterolateral limbs 

 short and marked by a broad strong furrow; ocular ridges low, but 

 clearly defined; frontal liml) short, gently convex, and sloping- into a 

 strong-, rounded furrow within the rounded, narrow, prominent fron- 

 tal rim. 



Surface smooth under a strong- lens. 



A head 10 mm. in length has a width of 11 mm. at the eye lobes. 



Formation and locality — Middle Cambrian. Base of Chang Hsia 

 formation, in oolitic limestone, about 2 miles southwest of Yen 

 CJhuang, Hsin Tai, Shangtung', China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



PROAMPYX Freeh, subgenus of PTYCHOPARIA. 

 Proumpijx FREcn, 1902; Lethseageognostica, I. Theil, Leth;ea Paheozoica, II, p. 66. 



Dr. Fritz Freeh proposed the genus Proampyx for Anomoeare 

 acuminatum Angelin on account of the projection of the frontal 

 border into a strong spine. He .said:" "The peculiar ver}' variously 

 formed group of Anomoeare aewninatum'' with pointed glabella, 

 seems to be the forerunner of Arajryx and is called Proampyx. The 

 difference from the typical Anomoeare with rounded head shield is 

 striking. The separation of the genus Proam)>y,r from the typical 

 Conocephalida? follows from the transitional forms Arionclhis sulea- 

 tus^ and A. dijformis.'' The spine of Am pyx aeumincdus is in well 

 preserved examples longer than in Angelurs illustration. The spe- 

 cies reminds most oi Ampyx nat<utus Dalman (Orthoceras limestone)." 



Doctor Freeh in his statement appears to have overlooked the fact 

 that the spine of the genus Ampyx is a spinose extension of the front 

 of the glabella, while the nasute projection of the frontal rim of 



« Lethfea geognostica, Pt. 1, Lethsea Palpeozoica, II, p. 66. 



^ Angelin, Tril. pi. xvii, fig. 7. 



c Anomoeare Angelin, Tril., pi. xvi, fig. 6. 



<^Idem, fig. 5. 



