560 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxii. 



segment ven^ short. The fixed cheeks are broad, convex, and subtri- 

 angular in outline, marked by post-marginal furrows, which continue 

 from the extremities of the occipital furrow. 



Remarks. — This species is a close ally of A. nasutus Dalman, but 

 it difi'ers from all illustrations of that species in its proportionally 

 greater width. The thorax and pygidium have not been observed, 

 the species being founded upon a single nearly perfect cranidium. 



Formation and locality. — Ki-sin-ling limestone, locality 29 C, near 

 Si-kia-pa, province of Ssi-ch'uan. 



ASAPHUS BLACKWELDERI, new species. 



Description. — Cranidium comparatively short and broad with the 

 axis obsolete, obtusely angular in front, the palpebral lobes large and 

 prominent, their anterior margins nearly opposite the middle point of 

 the head; in front of the eyes the lateral margins di\^erge gradually to 

 a point nearly halfway to the anterior margin, where thej^ are rather 

 broadly rounded, and then converge somewhat abruptly to the anterior 

 extremit}^; back of the eyes the lateral margins diverge rapidly and 

 curve backward to the posterior margin, the width of the cranidium 

 along its posterior margin being considerably greater than the distance 

 between the eyes. The occipital furrow and segment faintl}" devel- 

 oped. A slight median tubercle is situated at a point about halfway 

 between the line joining the posterior extremities of the e3'es and the 

 posterior margin, aside from which the surface of the cranidium is 

 apparentl}^ smooth. 



A free cheek is associated with this cranidium and possibly belongs 

 to the same species; its lateral region is differentiated as a rounded 

 marginal border, and its genal angle is produced into a rather strong 

 genal spine. 



The dimensions of the cranidium described are: Length, 8 mm.; 

 width between the eyes, 6 nun. ; width along posterior margin, 7.5 mm. 



Remarks. — The outline of the cranidium upon which this species is 

 established somewhat closely resembles that of A. expansus Dalman, 

 the t3^pical species of the genus, and both species are marked by a sim- 

 ilar small median tubercle near the posterior margin. This Chinese 

 species may be distinguished from its European all}', however, on 

 account of the obsolete glabella. If the free cheek which occurs with 

 A. hlack welder i reall>^ belongs to the species, this also will serve to 

 distinguish the two forms by reason of its strongly developed genal 

 spine, these spines being absent from the European species. 



This new species is named in honor of Mr. Eliot Blackwelder, who 

 collected the type specimens. 



Formation and locality. — Ki-sin-ling limestone, locality 20 B, near 

 Si-kia-pa, province of Ssi'-ch'uan. 



