390 VROCEEDINGS OF THE NATIONAL MUSEUM. 



situated on the anterior portion of the valve about one-third the length 

 of the shell from the anterior margin. 



Ohnervatiom. — This species resembles in many respects 0. matinalis ; 

 especially the Texan form referred to that species. The material is 

 poorly preserved, but it ai)pears to be clearly distinct from any 

 described species. Its surface characters are more like those of some 

 species of LirKjuMla, su(ih as 0. (7a) prindici, than those of the typical 

 American forms of Oboliis, such as 0. matinalis. 



The species is named in recognition of the ditticult and persevering 

 work of Mr. S. Ward Loner, curator of the Museum of Middlebury 

 College, who made a large collection of fossils, under the most adverse 

 circumstances, in the mountains of Colorado. 



FoniiaMon and locality. — lieddish sandstone, carrying a fauna inter- 

 mediate between the Cambrian and Ordovician. Cement Creek, 3 

 miles north of Hot Springs, and S to 10 miles southeast of Crested 

 Butte, Colorado. 



Ti/pe.—^o. 27303, U.S.N.M. 



OBOLUS NAMOUNA, new species. 



This form is closely related to O. matinalis. It diflers mainly in the 

 internal character of the dorsal valve. The area, in addition to the 

 narrow area of (>. matinalis, extends its lines of growth nearly onetifth 

 the length of the shell. The visceral area is shorter also than in 0. 

 matinalis, the central and interior lateral scars being closer together. 

 Owing to the somewhat imperfect character of the ventral valve, no 

 special points of ditference with the ventral valve of 0. matinalis can 

 be determined. It is associated on the same slabs of sandstone with 

 0. rhca. 



Formation and localiti/. — Middle Cambrian, St. Croix sandstone, Eau 

 Claire, Wisconsin. 



Typc.—^o. L>7304, U.S.N.M. 



LINGULELLA, a subgenus of OBOLUS. 



(Ihssina VuuAAVs, 1848; not delined. 



lAtujuhUa Saliku, 18(i6, Mem. Gool. Surv. (Jt. Brit., Ill, p. 333. 



Schmidtia Volhohtu, ISdi). 



Heretofore the data relating to TAnfiulella. have been too meager to 

 permit of detailed comparison with other genera. The presence of a 

 l)eculiar central channel in the cardinal area was the only character of 

 importance observed by Davidson that served to distinguish Lingiildla 

 from LiiKjula,^ and the illustrations of Lim/ulella ella, by Walcott, and 

 of L. relata,' by Hall, have added little. The present careful working 

 up of all the material relating to L. ella has brought out much more than 



I l?rit. Foss. Brach., Sil. Brach., 1866-71, Pt. 7, p. 55. 

 -This is not a Linsrulella. 



