4:M PALMOSTOLOGY 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. liratus and N. tnaximus, 

 yet they are of precisely the same order. 



In N. liratus the surface ornamentation is condensed and excessive. The 

 revolving striae and plications constitute the prominent features of the surface. 

 while the transverse striae, 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. liratus, 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. acraus. 



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 un weathered 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 stria; 

 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. 



