NO. 1395. CAMBRIAN BRACHIOPQDA—WALCOTT. 333 



granulated appearance. This type of surface occurs on O. (Z.) isse 

 and O. (Z.) upis. The anterior layers of the shell are marked by radi- 

 ating and concentric striae, and the interior of the shell has scattered 

 punctfe in addition to the radiating and concentric striaj. The shell is 

 relativel}" thick and formed of several layers or lamellaB in addition to 

 the very thin, outer, ornamented layer. 



The visceral area of the ventral valve is short, and the main vascular 

 sinuses are about half way between the center of the shell and the 

 lateral margins. In the dorsal valve the visceral area is well developed 

 beyond the center of the shell, and the vascular sinuses are farther 

 out proportionally than in the dorsal valve. The central and anterior 

 lateral muscle scars are placed on an elevated central ridge, on each 

 side of a sharp median septum. 



Observations. — This very pretty little shell occurs in great numbers 

 in the dark argillaceous shales with Hoeferia noetUngi Redlich. 

 Doctor Redlich states that it is the only species of the genus in the 

 collection sent to him. In the collections made by Dr. Fritz Noetling 

 1 lind associated with Hoeferia noetUngi., O. (Z.) ivanniecki., O. (Z.) 

 fuchsi, '' Mohergia-Acrothele ^m/??/^«/«" Redlich; also specimens of a 

 species of Hyolithes undescribed. 



Among the American species of Lingulelki., O. (Z.) vmnnlechi may 

 be compared in form with 0. (Z.) zetus and O. (Z.) oioeni. Its surface 

 is much like that of 0. (Z.) xijpis and 0. (Z.) ovus. It is distinct from 

 all described species when its form and surface are taken into consid- 

 eration, as there is no species with its subtriangular form that has its 

 granulated surface. 



Formation and locality. — Middle Cambrian. Zone of Hoeferia noet- 

 Ungi. Dark argillaceous shales, Khussak. Salt Range, India. The 

 formations containing this fauna are referred to the Middle Cambrian, 

 as there is no evidence that the Cambrian fauna of India above the 

 upper Annelid sandstone, as described by Dr. Fritz Noetling and Doctor 

 Redlich, is older. 



. OBOLUS (LINGULEPIS) EROS, new species. 



Ventral valve elongate with rostral slopes gradually converging so 

 as to form an accuminate beak. Surface marked l)y tine concentric 

 lines of growth and very tine, somewhat irregular, concentric stri^. 

 Rather large scattered puncta? occur on the interior surface. 



This species is represented by fragments and two broken ventral 

 valves; these indicate a length for the ventral valve of from 7 to 10 mm. 

 It is allied to O. {Llngulepis) acurnlnafm v^eeksl of the Middle Cam- 

 brian fauna of the Teton Mountains of Wyoming. 



Formation and loc<dlty. — Middle Cambrian. Chang Hsia limestone. 

 Three miles southwest of Yen Chang, Shantung, China. 



Collected by Mr. Elliot Blackwelder of the Carnegie Institution 

 expedition to China. 



Proc. N. M. vol. xxviii— 04 22 



