PLATE CV. 



Naotilos maqister. 



Page 422. 

 a«« Plates ri2, 107, 108. 

 Fig:. 1. A frajfment, jireserving two of the air-chanibei'S neai- the baae of the grand chamlier, with one of 

 the smaller ones at the distance of half a volution ; the impressions of the intervening air- 

 chambers and septa being marked upon the adhering matrix, showing the re-entrant chai-acter 

 of the volutions and the sinus in the septa on the dorsal side. The comparative diameter of the 

 two volutions, as presented in the fragment, are about as 65-115. The convex surface of the 

 larger air-chamber is flattened and distorted from coinpi-ession and weathering, which obseui-es 

 the siphuncle : from the same cause the concavity of the dorsal side of the large chambers has 

 been partially oblitei-ated, as shown in the outline of the flgure. 



The specimen is referred with some hesitation to N. inagisler; but the pifportions of the 

 pni-ts are essentially the same as in typical specimens of that species, and it is quite distinct 

 fii>m any other form. Lower part of the Hamilton group. Neai- Leotiardscille, Madison 

 ctnmty, N. Y. , 



Nautilus oribns. 



Page 4-20. 

 See Plate 61, 106. 

 The ventral aide of a compressed and imperfect chamber of habitation, with several air-chambei-s at the 

 base. The shell is partially preserved on one side, showing the transvei-se lamellose striae, and the impres- 

 sion of the same on the other side, which is exfoliated, showing numerous plumose, branching Bryozoans 

 which have adhered to the inner surface of the shell. From the Marcellus shale. Near RichmondvUU, 

 Schoharie county, N. Y, 



