NO. 1415. CA MBRIAN FA UNAS OF CHINA— WALCOTT. 1 1 



BRACHIOPODA. 



Genus ACROTHELE Linaarsson. 

 ACROTHELE MATTHEWI ERYX, new variety. 



In form, convexity, and size the ventral valve of the only specimen 

 representing this variety is very similar to the typical forms of 

 Acrothele Diattheim. The shell is partially exfoliated, and shows the 

 cast of the boss as a small oval pit about the pedicle opening- and two 

 narrow vascular sinuses that extend from a point nearl}" back of the 

 pit, forward and a little outward, about one-third the length of the 

 valve. 



The shell is built up of several layers of lamelUe that are smooth and 

 shin}^ on the interior, except where slightly roughened by slight vas- 

 cular markings and o])scure radiating strife; the outer surface is dull 

 and marked by concentric strise and lines of growth and numerous 

 fine, irregular, often anastomosing, elevated lines that give the surface 

 a rough appearance. 



The valve is nearly circular, with a diameter of mm. If this shell 

 were associated with Aci'otkeJe inatthewi in the Middle Cambrian rocks 

 of New Brunswick, I should not h(>sitate to identify it with that 

 species. In the absence of a series of specimens and specimens of 

 the dorsal valve, it is not certain that it is identical with Acrothele 

 inattlieivL On this account the varietal name is given it. 



Foniuitlo)) and locality. — Middle Cambrian, centi'al portion of 

 Chang Ilsia formation; 3 miles southwest of Yen Chuang, Hsin Tai, 

 Shangtung, China. 



Collected by Eliot Blackwelder, of the Carnegie Institution of 

 Washington Expedition to China. 



Genus SYNTROPHIA Hall and Clarke. 

 SYNTROPHIA ORTHIA, new species. 



General form irregularl}- oval, with the ventral view obtusely angu- 

 lar toward the apex; rounded, biconvex, with a deep mesial sinus at 

 the ventral valve and a strong median fold on the anterior half of the 

 dorsal valve. 



Surface smooth with the exception of a few concentric ,striiv and 

 lines of growth. 



The venti'al valve has a strong median sinus that occupies about one- 

 third of the width of the valve at the anterior margin and projects for- 

 ward to tit into the sinus in the front of the margin of the dorsal valve; 

 the sides of the median sinus are elevated, and with the downward 

 curving lateral slopes form a strong, roimded ridge on each side of the 

 sinus; none of the specimens in the collection show the area, but from 

 the profile of the valve it must have been of moderate height with a 

 rather sharp apex curving over it. 



