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Geological Formation and Locality. In limestone of the age 

 ©f the Niagara Group, Racine, Wisconsin. Dr. P. R. Hoy, 

 T, J. Hale, James Hall. 



GENUS CARYOCYSTITES, Von Buch. 

 CARYOCYSTITES cylindricum, (n. s.) 



Description. Body elongate-obovate, or sub-cylindrical; 

 rounded at top and abruptly contracted at base near the junction 

 with the column ; basal plates undetermined. The first range 

 above the basal series consists of eight elongate hexagonal plates, 

 their length once and a half the greatest width, gradually ex- 

 panding in width from below upwards. These are succeeded by 

 a second, third, fourth and fifth range of eight plates in each, all 

 somewhat regularly hexagonal, their length a little greater 

 than the width. Of these, the fourth range is usually the 

 widest, situated at a little more than one third the length of 

 the body from the summit, and at the point of greatest diameter. 

 The sixth range above the basal plates are much smaller than 

 the others, and narrowest at their upper ends. Alternating 

 with the last there is a seventh range of smaller plates, sur- 

 rounding those of the summit and enclosing the summit open- 

 ings. Column small, round, rapidly tapering below the point 

 of attachment. Surface characters unknown. 



The above description is drawn from specimens which are 

 casts. The divisions of the smaller plates are seen, and one 

 of the apertures of the summit is well marked on several indi- 

 viduals ; but the ovarian aperture (which is described as being 

 on the side towards the lower part of the body in Caryocys- 

 TITES,) has not been satisfactorily determined. The surface 

 appears to havo been coarsely granulose. 



Geological Formation and Locality. In limestone of the age 

 of the Niagara group at Racine, Wisconsin. Dr. P. R. Hoy, 

 James Hall. Grafton, Wis., Edward Daniels. 



CARYOCYSTITES alternatum, (n. s.) 



Description. Body extremely elongate, sub-cylindrical, the 

 greatest diameter near the apex, extremity with irregular 

 constrictions near the middle in some specimens. Summit 

 irregularly rounded, flattened, or depressed on the side of 

 the aperture ; base gradually tapering to the summit of the 

 column. The body is composed of several (twelve) ranges 

 of plates, varying in size and shape ; in some of the ranges 

 they are large, mostly octagonal, eight in number, in a range ; 



