332 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxviii. 



The shell is thick, the anterior portions being made up of numerous 

 lamella' oljlique to the exterior surface, in this respect resembling- 

 some of the species of Olxdnx. having- thick shells. The exterior 

 surface is mai-kecl by concentric lines of growth, with very line, 

 somewhat irregular strije between them. These show very distinctly 

 on the anterior portion of the shell. Farther back they become very 

 irregular, giving a crenulated appearance to the stria3 and lines of 

 growth, and the surface looks as though it were formed of thin, 

 imbricating scales or lamellae. 



The surface of O. (Z.) uph suggests that of <>. ( ^¥estoni(l) euglypJms^ 

 but I have been unable to Und traces of the transverse lines character- 

 istic of Wed<>ii/<t. 



Formation and locality. — Middle Cambrian. One mile west of 

 Cherokee, San Saba County, Texas. 



OBOLUS fLINGULELLA) FUCHSI Redlich. 



Lmgidella fiichd Redijch, Pal. Indica, new ser. , I, 1899; Cam])riaii Fauna, 

 Eastern Salt Range, p. 7, pi. i, tigs. lOa-e. 



In the collection received from Doctor Noetling 1 tind that there 

 occurs in association with O. {L.)(rann!ecl'l a small, elongate form that 

 appears to be identical with L. fncJixl of Redlich, Doctor Redlich 

 states that his L. fucJisi occurs in hai"d clay a})ove the lower magnesian 

 sandstones which rest on the shales containing (J. (Z.) iranniccl'l. If 

 my identification of the species is correct, 0. (Z. ) iranniecliho.^ '^i 

 greater vertical range, or there may have been some error in identifi- 

 cation and in the labeling of the zone from which the original speci- 

 mens were obtained. The identification of the species in the material 

 before me is based on the form of the venti-al valve, as shown hy 

 Doctor Redlich's figure 10c. Dorsal valves differ materially from his 

 illustration; but in another specimen a little pit mentioned l)y Doctor 

 Noetling is shown, also two ridges that leave a concave hirrow in the 

 central portion of the cast of the valve. These- are the lines of the 

 main vascular sinuses. 



Format/on and locality. — Middle Cambrian. Zone of IJocferia 

 jtoetling!, in dark argillaceous shales, Khussak, Salt Range, India. 



OBOLUS (LINGULELLA) WANNIECKI Redlich. 



lAmjulella icanniecki Redlich, Pal. Indica, new ser., I, 1899; Cambrian Fauna, 

 Eastern Salt Range, p. 7, pi. i, figs. 9a-d. 



General form ])r()adly ovate, with the ventral valve obtusely accu- 

 minate and the dorsal valve rounded subtriangular; convexit}" moderate 

 in the specimens embedded in argillaceous shales. There is consider- 

 able range of variation in the outline of the valves. The surface of 

 the shell is marked by concenti-ic lines of growth and very fine, closely 

 undulating- raised striae that inosculate so as to give the surface a 



