PLATE CXXVI. 
Nautilus Hyatti. 
Page 37. 
Fig. 1. Dorsal view of a plaster cast, taken from the natural mould, showing the form of the tube, and the 
well-preserved surface ornamentation. • 
Hamilton group. C^imherland, Maryland. 
Nautilus okiens. 
Page 37. 
Fig. 2. Longitudinal section of the individual figured on plate 106, Pal. N. Y., vol. v, pt. ii, showing the 
capacity of the grand chamber, the septa, and remains of the moniliform siphuncle. The inner 
volution has been filled with calcite, and the septa removed, but a portion of the beaded siph- 
uncular tube remains in situ. 
Hamilton shales. Richmondville, Schoharie county. 
Nautilus parallelus.. 
Page 38. 
Fig. 3. Ventral view of the specimen, showing the gradual enlargement of the tube and the parallel re¬ 
volving ridges of the test. 
Fig. 4. Id. Lateral view, showing the curvature of the tube, the angular periphery, and the concavity of 
the last septum. The parallel I'evolving lidges ai-e seen to be less frequent than on the ventral 
side. 
Fig. 5. Id. The last sexitum, as xireserved in the specimen, showing the subcentral position of the siph¬ 
uncle, and the lenticular transvei-se section of the tube. The dorsal side is more convex than 
the ventral, and the carinations of the lateral angles are directed upward and outward. 
Coal measures ? Ohio ? 
Nautilus (Discites) Marcellensis. 
Page 39. 
Fig. 6. Dorsal view of a well-preserved individual, illustrating the essential features of this species. The 
variation in the enlargement of the dorsal, ventral and lateral sides is well contrasted. The 
dorso-lateral margin is continuous and slightly reflected, while the ventral angles are marked 
by a row of nodes. A single revolving line over the siphuncle indicates its position and that of 
the ventral side. Four segments of the siiihuncle are exposed, showing its concavesides within 
the cavities of the air-chambers. A portion of the test is adhering to the ventrum, preserving 
the cancellate ornaments and the broad sinus of the concentric striae over this side of the tube. 
Goniatite limestone. Manlius, Onondaga county. 
Gyrooeras Stebos. 
Page 36. 
Fig. 7. Lateral view, showing the enrollment of the tube and the strong elevated nodes ornamenting the 
lateral angles. Traces of the transverse striae are preserved near the aperture. 
Waverly group. Warren, Pennsylvania. 
