NO. 1395. CAMBRIAN BRA CHIOPODA— WALCOTT. 323 



Authors have referred frequently to the resemblances between 

 speeies of Obolella and Elh((i}ia desiderata. These do not appear to 

 exist except in a superficial manner. Obolella is a stage in the evolu- 

 tion toward the Siphono-tretidte, while Elkania is toward the Tri- 

 merellida'. 



ELKANIA BELLULA, new species. 



General form elongate oval; biconvex; beaks marginal. Surface 

 marked by line concentric stritv of growth that occasionally form 

 varacies and small ridges near the umbo; the inner layers or lamallfe 

 have radiating striae in addition to concentric stri^. 



The shell is relatively thin and small. It rarely exceeds 2.5 mm. 

 in length and a little less in width; the dorsal valve is a somewhat 

 shorter than the ventral. 



Ventral valve subacuminate, moderately convex; the interior shows 

 a reversed cardinal area attached to the bottom of the valv^e and below 

 the plane of the margins of the valve; the pedicle groove is strong; 

 the line of demarcation between the cardinal area and the bottom of 

 the valve is indefinite, as the margin of the area and the body of the 

 shell have been merged into each other; the transmedian and antero- 

 lateral muscle scars are outside the main vascular sinuses and near 

 the margin of the valve; the central scars and middle and outside 

 lateral scars are supposed to have been attached within an area which 

 is largely on the front slope of the thickening of the umbonal portion 

 of the valve. 



The dorsal valve has a short reversed area; the antero-lateral muscle 

 scars were probably well advanced toward the front, judging from 

 traces of the length of the visceral cavity. 



The vascular markings include the main vascular sinuses in the ven- 

 tral valve and traces of the \ isceral area in the dorsal valve. 



This pretty little shell is much like a small species of Lingtdella in 

 its exterior appearance; the interior connects it with Elkania. I know 

 of no species closely related to it. 



Eorniation and locality. — Upper Cambrian. Limestone about 3 

 miles south of Benders Pass, Silver Peak Range, Nevada. 



SCHUCHERTINA, new genus. 



The description of the type species is that of the genus and species, 

 as but one species is known of the genus. 



Type. — ScliucheTtina camhria. 



The generic name is given in recognition of the admirable work that 

 Prof. Charles Schuchert has done on the fossil brachiopods. 



SCHUCHERTINA CAMBRIA, new species. 



Shell subovate, with valves obtusely acuminate; biconvex. Sur- 

 face marked by concentric lines and striae of growth and fine radiating 



