272 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvin. 



Oklahoma Territory. Cold Creek, north end of gorge opposite north 

 end of Sponge Mountain, Llano Count3% Texas, Conglomerate series 

 and 50 feet above, St. Francis County, Missouri. Upper Cambrian. 

 Lower part of Arbuckle limestone. At small hill 2 miles southwest of 

 Signal Mountain, Wichita Mountains, Oklahoma Territory. Reagan 

 formation, top beds, west side of Honey Creek near SE. corner sec. 

 ;:55, T. 1 S. , R. 1 E. ; NW. i sec. 1, T. 2 S., R. 1 E., Ardmore quadrangle. 

 Northwest extremity of Arbuckle Mountain, about 4 miles east of 

 Homer, Indian Territory. 



PLECTORTHIS WICHITAENSIS LAEVIUSCULUS, new variety. 



A variety with small, narrow, numerous ribs is given the above 

 name. Many graduations exist between it and the typical forms of 

 P. wichitae7iKlf<. 



Foniiafioii and lucaUty. — Same as P. iincldtaensli< in Oklahoma and 

 Indian Territories. 



PLECTORTHIS WIMANI, new species. 



This shell is distinguished from /*. <-hri'<tl<uil^ >xn6. P. dmunis by the 

 rounded, narrow, simple ribs, less transverse and more rounded out- 

 line. A ventral valve shows a well-defined pseudospondyliuni with 

 the tripartite division as seen in Plectortlih reinnifha. Two strong 

 main vascular sinuses extend forward from the lateral divisions of the 

 umbonal cavity nearly to the front of the valve, corresponding in 

 position to those of the dorsal valve. The cast of the dorsal valve 

 indicates the presence of rather strong crura, crural plates, teeth 

 sockets, and delthyrium. 



The ventral valve is rather strongly convex and dorsal valve about 

 one-half as much so. The average size is 6 mm. to 7 mm. in diameter, 

 the ventral valve being about 1..5 mm. larger than the dorsal. The 

 largest ventral valve in the material available for study has a length 

 of 9 mm. 



The species is named after Dr. Carl Winian in recognition of his 

 excellent work on the cambrian faunas of Sweden. 



Forynation and locality. — Upper Cambrian. Ceratopyge zone. 

 Limestone at Oland, Borgholm, Sweden. Limestone at Slemenstad 

 west of Christiania; black argilaceous shale, Christiania, Norway. 



PLECTORTHIS 2 Sp. ? 



Dr. J. F. Pompeckj" mentions two species of Orthis from the 

 Middle Cambrian green Paradox ides shales of Bohemia which appear, 

 from the illustration, to belong to the genus Plectorthis. The mater- 



''Jahrbiich k. k. geol. Reichsanstalt, XLV, p. 514, pi. xv, fig. 6 and fig. 7. 



