Contributions to Invertebrate Palseontology . 593 



globular within the aiiriculations, the inner ones projecting into and strongly 

 modifying the form of the aperture, which is transversely reniform and ex- 

 panded at the sides, but not in front. Surface of the shell not known from 

 Ohio specimens. 



The Ohio specimens referred to this species are all quite imper- 

 fect; being imbedded in compact limestone and the shell replaced 

 with crystals of carbonate of lime, they do not give the entire 

 characters, so their correct reference to B. Isevis Hall is somewhat 

 doubtful. The species as seen on entire individuals from the origi- 

 nal locality is slightly keeled on the outer volution, and marked, 

 rather faintly, by curved transverse striae parallel to the margin of 

 the aperture, and indicates a rather shallow but broad notch in the 

 margin of the aperture. 



Formation and Locality. — The originals of the species are from 

 Spergen Hill and Bloomington, Indiana; and the Ohio specimens 

 are known from Nevvtonville and Maxville, Ohio, in the Maxville 

 limestone. 



Belleroplioii alternodosus. 



Plate XIV, figs. 17-19. 



Bellerophon alternodosus Whitf., Ann. N. Y. Acad. Sci., 1882, p. 225. 



Shell of about a medium size, and somewhat subglobose in general form, 

 with an appearance of being slightly flattened on the dorsum in immature 

 specimens ; while on the adult forms, the dorsum is marked on the outer half 

 of the body-volution by a double series of rounded nodes, those on one side 

 of the centre alternating with those of the other side, and the inner margins 

 of the two series interlocking with each other. Aperture broadly elliptical, 

 strongly modified by the projection of the preceding volution, on the inner 

 margin. Auriculations largely developed and slightly reflected. Axis very 

 distinctly perforate. Inner lip somewhat callous on the protruding inner 

 volution. Surface of the shell, so far as can be ascertained, marked only by 

 lines of growth, beyond the nodes mentioned. 



The species is somewhat similar in general form to B. 3Iont- 

 fortianus N. and P., from the Coal Measures, in its general form, 

 but does not possess the strong transverse folds nor the carina 

 between the lines of nodes marking the dorsum. It also differs in 

 the alternating positions of the nodes. 



Formation and Locality. — In the Maxville limestone at New- 

 tonville, Ohio. Collection of Columbia College, New York. 



