The J'aiiita of ilic Maxvillc Limcsioiic. 413 



NAUTILUS PAUPER— Whitfield. 



1882. Nautilus pau[>cr. Whitfield, Ann. N. Y. Acad. Sci., Vol. II, p. 220. 



Maxville limestone : Near Rushville, Ohio. 

 1891. Nautilus pauper. Whitfield, Ann. N. Y. Acad. Sci., Vol. V, p. 595, 

 pi. 14, fig. 23. 

 Maxville limestone: Near Rushville, Ohio. 

 1895. Nautilus pauper. Whitfield, Geol. Surv. Ohio, Vol. VII, p. 481, 

 pi. 10, fig. 23. 

 Maxville limestone: Near Rushville, Ohio. 



Description. — ^ "Shell somewhat helow the medium size, 

 and consisting of about two and a half volutions, which increase 

 rather rapidly in size, and are so coiled as to expose almost the 

 entire diameter of the inner coils in the umbilical cavity ; the 

 outer one embracing only the dorsal [ventral] siu'face of the 

 inner volution. Volutions quadrangular in form , with lateral 

 diameter only about two-thirds as great as the dorso-ventral 



Fjg. 34. — A^autilus pauper. A view of the outer chamber and the im- 

 pression of the inner coils. (After Whitfield.) 



diameter, while the dorsal and ventral stu"faces are nearly ver- 

 tical [perpendicular] to the plane of the sides, so far as can 

 be determined from the specimen on hand; or possibly the dorsal 

 [ventral?] surface may be slightly rounded. The sides of the 

 shell are marked b\' a faint, narrow, revolving sulcus bor- 

 dering the margin of the umbilicus, and ])v a corres]iondingIy 

 faint ridge close to the dorsal margin ; while a much stronger 

 rounded ridge occurs on the surface at about one-third of the 



