922 THE PALEONTOLOGY OF MINNESOTA. 



[Bucanopsls, 



this species sometimes look very much as though they might be a larger variety of 

 Protowarthia granostriata. Yet this is most certainly not the case, since the species 

 possesses a slit-band and the aperture of a true Bellerophon. When neither of these 

 features is preserved, then it is distinguished from the Protowarthia by its open 

 umbilicus and larger size. 



.Formation and locality. Lower part of the Loraine group and upper part of the Utica group at 

 several localities in the vicinity of Cincinnati, Ohio. 



Collection. E. O. Ulrich (7 specimens). 



Genus BUCANOPSIS, n. gen. 



Bellerophon (part.), HAI..L, MEEK, DE KONINCK, McCoy, D'ORBIQNY, and other authors prior to 

 1880. LINDSTROM, 1884, Silurian Gastropoda of Gotland. 



Bucania (part.), WAAOEN, 1880, Palasontologica Indica, ser. 13, pt. 2, pp. 130 and 150. KOKEN, 1889, 

 N. Jahrbuch f. Mineralogie, etc., Beilagehand vi, p. 379. 



?Euphemus (part.), McCoy, 1844, Synopsis Carb. Foss. Ireland, p. 25. 



For generic characters see page 853. 



The greater part of the species which we propose to classify under this generic 

 name were originally described as of Bellerophon, an arrangement that was quite 

 satisfactory to paleontologists till 1880 when Waagen proposed to separate them on 

 account of their spiral surface sculpture. In this we think he was fully justified, 

 because extensive studies of the Bellerophontacea prove conclusively that the surface 

 markings deserve a high rank among the characters that are available to the 

 systematist who seeks to subdivide the group into natural and convenient generic 

 sections. But, as we shall show in discussing that genus, both he and Koken, who 

 adopts Waagen's proposition, are wrong in extending the application of Hall's 

 Bucania to all the spirally striated bellerophontids. Bucania must be restricted to 

 species of the type of B. sulcatina, which is quite different in other respects from the 

 Devonian and later Paleozoic shells that make up the bulk of the species referred 

 by them to Hall's genus. The surface markings even are not exactly the same in 

 the two groups, they being straight and parallel with the direction of the whorls in 

 Bucanopsis while in true Bucania they are wrinkled, interrupted and more or less 

 oblique in direction. 



It seems very clear to us that Bucanopsis was developed from Bellerophon and not 

 from Bucania. Every character of the genus, excepting the revolving lines, corres- 

 ponds with the former and is more or less different from the latter. A comparison 

 of the figures of species described in this work alone can scarcely fail to convince 

 students that this is really a fact, and the same must continue to grow more obvious 

 when they extend their comparisons to Upper Silurian, Devonian and Carboniferous 

 Bellerophontidce . 



