Contributions to Invertebrate Palaeontology. 531 



Goiuplioceras Sciotense. 



Plate VIII, fig. 4 ; Plate IX, fig. 2 ; Plate X, figs. 6 and 7. 



Gomphoceras Sciotense Whitf., Ann. N. Y. Acad. Sci., March, 1882, p. 208. 



Shell of medium size or smaller, short obconical in form, or rapidly expand- 

 ing from the apex npward ; slightly flattened in a dorso-ventral direction, 

 giving a broadly oval transverse section, which is a little more flattened on the 

 dorsal than on the opposite side, in the more perfect specimen, but may not be 

 constantly so in all individuals. Septa shallow, arranged at nearly equal dis- 

 tances from each other in the larger parts, and numbering about seven in au 

 inch, except near the outer chamber, wliere there are usually one or two more 

 closely arranged. The outer chamber is proportionally short, and rapidly con- 

 tracted in the upper part to about one-half the diameter below, to form the 

 transversely sub-triangular or obscurely trilobed aperture, which is rounded 

 at the lateral extremities, straightened on the dorsal side, and provided with a 

 moderately deep but rather narrow sinus on the ventral margin. Siphuncle 

 proportionally small, and situated close to the dorsal side. 



Only two individuals have thus far been observed, and these 

 show some slight variation in the form of the transverse section 

 and in the proportional length of the outer chamber; the one re- 

 taining the chambers being shorter above, and more flattened on the 

 dorsal side than the other. In this specimen, the septa are some- 

 what obliquely arranged, being highest on the dorsal side, which 

 may, however, be owing to oblique compression in the matrix. The 

 individuals, being both internal casts, have afforded no opportunity 

 of observing the surface structure. 



Formation and Locality. — In the limestone of the Upper Held- 

 erberg group, at Smith and Price's quarries, near Columbus, Ohio. 

 Collected by Mr. Hyatt. 



Genus CYRTOCERAS Goldf. 



Cyrtoceras cretaceum. 



Plate VIII, figs. 2 and 3. 



Cyrtoceras cretaceum Whitf., Ann. N. Y. Acad. Sci., March, 1882, p. 209, 



Shell of medium size, somewhat moderately expanding in its upward growth 

 to the base of the outer chamber, from which point it again contracts to the 

 aperture ; the increase not always regular, but in some individuals more 

 abruptly expanding above than below. Shell slightly curving throughout its 

 length, appearing less arcuate in the upper portion, owing to the contraction 

 of tlie outer chamber toward the aperture. Transverse section oval, widest 

 in a lateral direction, and with the inner surface much less arcuate than the 

 outer or dorsal surface. Outer chamber proportionally short, the length not 



