112 lU'LLETIN 164, UNITED STATES NATIONAL MUSEUM 



The surface is marked by very i)eculiar ripplelike striations. 



Altlioiiirh this species i.s founded on i)y«ridia alone. I give these 

 rcnuirkable :speciniens a new specific name, since the features are very 

 characteristic. 



Formation aiul JocaVit]i. — T'ppcr Ordovician : Near (^hao-hua, 

 ►Szechwan, China. 



C'o^2//>C6\— U.S.N.M. Xo. 8376T. 



Genus ASAPHUS Brongniart, 1822 



ASAPHUS ASIATICUS, new species 



Plate 39, Figukes 11-17 



A number of curious cephalia and rather well-preserved associated 

 pygidia Avere included in Louderback's collection from central 

 China. As I could not find a whole specimen or even a perfect 

 cephalon in this collection, I am not sure to which genus these speci- 

 mens really belong. The general features of the cephalia and pygidia, 

 however, resemble characters of Asaphus, to which I am tentatively 

 referring them. 



Description. — Ce])halon. exclusive of the free cheeks, somewhat 

 elongated-circular in outline. Glabella circular, moderately convex, 

 without perceptible traces of the glabellar furrows; dorsal furrow 

 shallow but rather distinct ; palpebral lobes very faint, scarcely 

 noticeable; frontal rim broad and distincth^ concave. 



The associated pygidia are rounded, subtriangular in outline, 

 and about two-thirds as long as the width of the anterior margin, 

 moderately convex ; axial lobe convex and tapering gradually 

 posteriorly ; it is very faintly divided by about 5 or 6 transverse 

 furrows into 5 or 6 rings and a rather long terminal section ; 3 or 4 

 ankylosed pleural segments are outlined on the pleural lobes by 

 furrows. 



Surface of the ce])halia and pygidia is marked by very fine undu- 

 lating striations with associated, sometimes small, pits, ornamenta- 

 tions wdiich are naturally most conspicuous on the cephalia. 



Formation and locality. — Ordovician : Near Huang-pa-yi, Shensi, 

 China. 



6'o////>r6-.— U.S.N.M. No. 83768. 



Genus ISOTELOIDES Raymond, 1910 



ISOTELOIDES species undetermined 

 Pr.ATK 22. FlCilTRE 10 



A single distinct pygidiuiu occurs in the lower fossil horizon of 

 the Ssuyen forinati<m. This specimen (U.S.N. M. No. 83769) is 

 referable to IsoteloldcH.^ since it has a smooth surface with a slightly 



