I 
PLATE CVII. 
Nautilus magister. 
Page 422. 
See Plates 62, 105, 108. 
Fig. 1. The convex side of 1 a septum of a large individual, showing the elliptical form with the broad sinus 
on the dorsal side, and the siphuncle with the surrounding areola. 
Fig. 6. A fragment preserving the apical portions of the volutions, showing the fractured margins of the 
air-chambers from exfoliation, and the deep umbilicus. 
Fig. 7. A fragment of one of the small inner volutions, showing the form and proportions of the siphuncle, 
in its passage through the air-chambers, and its constriction at the septa. 
Fig. 8. A longitudinal section of the smaller part of the outer volution, with a part of the inner volution, 
showing the depth of air-chambers, the form and proportions of the siphuncle, etc. The figure 
is incomplete in the upper convex portion, the septa and chamber filling having been broken 
away, and the outline is not continued. The specimens are all from the Hamilton group. 
Town of Hambwgh, Erie county, N. T. 
Nautilus bucinum. 
Page 412. 
See Plates 60, 106, 109. 
Fig. 2. A fragment preserving four air-chambers and the base of the grand chamber. 
Fig. 3. A septum showing the form of the transverse section and the position of the siphuncle. From 
the decomposing semi-calcareous shales of the Hamilton group, at Pratt's Falls, Onondaga 
county, N. T. 
Fig. 4. A fragment preserving a part of the chamber of habitation with several attached air-chambers. The 
test is partially preserved, and the fine cancellating striae are well defined. 
Fig. 5. An enlargement of the surface of figure 4, showing the character of the surface-markings of the shell. 
From the shales of the Hamilton group on the east shore of Cayuga lake, N. Y. 
