258 PROCEEDINGS OF THE ACADEMY OP 



Genus GOMPHOCERAS, Sowerby, 1839. 



GOMPHOCERAS SACCULUM, M. & W. 



Shell *mall, subfusiform, or clavate, very slightly arched ; a little com- 

 pressed at right angles to the plane of the curve, particularly the nonseptate 

 part, which is more convex on the outer side of the curve than the inner; 

 most ventricose a little above the last septum, thence tapering gradually to 

 the lower extremity and towards the aperture, near which latter there is a 

 slight constriction. Section transversely a little oval near the middle of the 

 shell, and more decidedly so above, but nearly or 'quite circular towards the 

 lower extremity. Aperture transversely oval, its smaller diameter being 

 about two-thirds the greater ; lips faintly sinuous at each end of the aperture, 

 and at the middle of the dorsal side. Septa but slightly concave ; (distance 

 between them not distinctly determinable from the specimen examined). 

 Siphon very small ; placed on the line of the shorter axis of the septa, about 

 twice its own breadth from the dorsal or outer side of the curve. Surface 

 marked only with small annular strise, slightly arched backwards near each 

 end of the aperture, parallel to the faint sinuosities of the lip. 



Length of specimen, imperfect at the smaller extremity, 127 inch ; do. of 

 nonseptate part, OG7 inch ; greatest transverse diameter of do., 053 inch ; 

 shorter diameter of do. at same part, - 42 inch. Apical angle of septate half 

 of the shell, measuring along each lateral margin, 24 p . Breadth of aperture, 

 0*33 inch ; smaller diameter of do., - 22 inch. 



This little shell has the general habit and appearance of Gomphoccras, and 

 yet differs from the typical forms of that genus in being slightly arched and 

 not having its aperture so remarkably contracted. In being a little curved, 

 it more nearly resembles Phragmoceras, though its curvature is less decided. 

 It is also worthy of note, that the comparatively small contraction of its 

 aperture is mainly on dorsal and ventral margins, while in Gomphoceras and 

 Phragmoceras the contraction is mainly on each lateral margin. In several 

 respects it approaches Oncoceras, Hall, and it is even possible that we would 

 be more nearly correct if we were to call it Oncoceras sacculum. Still it differs 

 from the type of that group in beiug less curved, and compressed dorso-ven- 

 trally, instead of laterally, as well as in having its siphon not quite, though 

 nearly marginal. 



Locality and position. White Sulphur Springs, Delaware County, Ohio. 

 Hamilton Group of Devonian Series. 



Gomphoceras (Apioceras) turbiniforme, M. & W. 



Shell rather small, turbinate, or obovate, very slightly unsymmetrical ; sec- 

 tidn circular, or nearly so ; chambered part rapidly expanding, with sides 

 slightly convex above. Non-septate part very short, or three times as wide 

 as long, rounding in abruptly above ; aperture contracted, but exact form 

 unknown. Septa only moderately concave, nearly equidistant at all points, 

 excepting near the outer chamber and the apex, where they are more 

 crowded ; at about the widest part of the shell, separated by spaces equalling 

 one-eighth its greatest diameter. Siphon small and marginal. Surface 

 nearly smooth, or with only fine lines of growth. 



Length of a specimen not quite complete at the smaller extremity, 1*16 

 inch. Greater breadth (at the junction of the septate and non-septate parts), 

 1 inch ; smaller diameter at the same place, - 90 inch. Greater diameter at 

 the smaller extremity, 0-32 inch ; smaller do. at same place, 0'30 inch. Di- 

 vergence of apical angle, 30. 



This is a very short turbinate species, somewhat like G. beta, Hall, (18th 

 Report Regents, pi. 7, fig. 1), but diners in being proportionally shorter and 

 more ventricose, and in having the septa proportionally more crowded. It 

 shows eleven septa in a space of three-quarters of an inch below the last one, 

 while G. beta is described as having only seven or eight in the same space. 



[Dec, 



