PLATE CVT. 
Nautilus cayus. 
Page 416. 
Fig. 1. The concave dorsal side of a part of the outer chambered volution, showing the impression and the 
sinuosities in the septa, caused by the re-entrant volution. 
Fig. 2. The ventral side of the specimen, showing the great depth of the air-chambers. 
Fig. 3. Lateral view of the same, the open umbilicus and the curvature of the volution. From the shales 
of the Hamilton group. Near Cumberland, Md. 
Nautilus bucinum. 
Page 412. 
See Plates 60, 107, 109. 
A lateral view of an imperfect specimen which has been partially crushed somewhat obliquely in a 
dorso-ventral direction. 
The ventral side of the preceding specimen, showing the lateral expansion of the chamber of habita¬ 
tion and adjacent air-chambers. The surface is partially covered by a tubular parasite. 
Cazenovia, N. Y. 
The ventral side of a specimen which preserves nearly its natural proportion, showing the deep and 
gradually expanding chamber of habitation. The shell is partially preserved in a macerated 
condition, and is marked by the impressions of branching tubular Bryozoans. The opposite 
side of the same specimen is shown on plate 58, figure 4. Solsville, Madison county, N. Y. 
A longitudinal section of a small specimen, which shows the depth of the outer, chamber, with the 
character and concavity of the attached air-chambers. Quarries north of Sherburne, Chenango 
county, N. Y. 
Fig. 4. 
Fig. 5. 
Fig. 6. 
Fig. 7. 
Nautilus oriens. 
Page 420. 
See Plates 61, 105. 
Fig. 8. A lateral view of a young or medium-sized specimen, showing the principal part of the chamber of 
habitation, the depth of the air-chambers and the deep umbilicus. From the Marcellus shales. 
Near Richmondville, Schoharie county, N. Y. 
