

24 



in others they are much smaller, pentagonal or hexagonal, and 

 about twico as many as in the ranges of larger plates ; these 

 ranges alternate with each other. Near the summit, between 

 what appears to be the eleventh and twelfth ranges of plates 

 from the base, there is a distinct lateral opening, with another 

 somewhat smaller opening more nearly on the summit, corres- 

 ponding with the mouth and anal opening as described by 

 Von Buch ; but the lower lateral aperture (ovarian aperture) 

 has not been recognized; most of the specimens being broken 

 near the base, and weathered on one side. Surface characters 

 unknown. 



The specimen, like thoso of the last species, are casts, but 

 the characters given above are distinctly seen in several indi- 

 viduals. The structure of the body does not very well corres- 

 pond with the generic characters of Caryocystites, and it may 

 be necessary, when more perfect specimens are discovered, to 

 designate it by another name. 



Geological formation and hcaliiy. In limestone of the age 

 of the Niagara Group. 



Collector. T. J. Hale. 



BRACHIOPODA. 



LINGULA polita, (n. s.) 



Description. Shell small, short ovate, the greatest width near 

 the front, which is broadly rounded; beaks obtusely rounded; 

 valves moderately convex, with prominent um bones. Surface 

 glabrous, or marked by very fine concentric lines of growth. 



The interior of the ventral valve shows a distinct spatulate 

 muscular impression in the centre, with raised margins, and 

 fainter impressions at the sides. There is an obtuse dental 

 process on each side of the rostral cavity. 



This species differs from L. prima in the prominence of the 

 of the umbones, and in being destitute of lamellose concentric 

 lines of growth. The shell was referred by Dr. D. D. Owen 

 to Obolus, but I am unable to find satisfactory evidences of 

 the features of Obolus ; neither do the characters correspond 

 with true Lingula. 



Geological formation and locality. In Potsdam sandstone, 

 in beds below those containing Conocephalus and ArioneUus, 

 at Trempeleau, Wisconsin. Edward Daniels, James HaU. 



LINGULA aurora, (n. s.) 



Description. Shell of moderate size, broadly subovate ; beak 

 appressed, obtusely pointed; cardinal borders strongly diverging. 



