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PALAEONTOLOGY OF NEW YORK. 
The forms of Nautilus described in the preceding pages present a most 
remarkable similarity in the plan and style of the surface-markings; although, 
at first view, there seems little similarity between N. Urdus and N. maximus, 
yet they are of precisely the same order. 
In N. Urdus the surface ornamentation is condensed and excessive. The 
revolving strim and plications constitute the prominent features of the surface, 
while the transverse strim, in well-preserved specimens, are likewise conspicuous. 
The absence of the test in most of the specimens renders it impossible to know 
fully the original aspect; but this may be inferred from the impressions upon 
the casts of the interior. The specimen given as N. Urdus, var . juvenis, presents 
a subdued condition of the surface characters, which are more fully developed 
in the typical specimens of the species. The same character, in a still more 
subdued condition, marks the surface of N. bucinum, N. cavus, and, in a lesser 
degree, that of N. cornulum, while it is still preserved in the extremely fine 
markings on the surface of N. acrceus. 
These surface features, in an extenuate and obsolescent condition, are still 
observable in the surfaces of N. oriens, N. maximus and N. magister. In specimens 
of N. oriens, which are partial casts of the interior, the entire lateral face is seen 
to be marked by low, undefined, revolving plications, which are sometimes so 
obscure as to be seen only by reflected light. A similar character, with wider 
and scarcely distinguishable low folds or undulations of the surface, is visible 
on the chamber of habitation, near the aperture. In all cases wherever any 
portion of the shell is retained, or even in the unweathered casts, the fine, 
thread-like, transverse striae are present, differing in no respect from those on 
the surface of N. liratus. In one example where a portion of the outer chamber 
of N. oriens, near the aperture, is preserved in black shale, the transverse striae 
are extremely conspicuous, with only narrow revolving striae perceptible, 
having precisely the appearance of an extenuate portion of the surface of 
N. liratus, var. juvenis. The surface characters of N. maximus and of N. magister 
are less distinctly preserved; but in the small, remaining portions of the test, 
or its imprint upon the cast of the interior, the same style of marking is 
observed. 
