351 



Nautilus ferox. (N. sp.) 



Description. — Shell large, apparently eight or nine inches across; 

 whorls rapidly increasing, the third measuring nearly three inches in the 

 dorso-ventral diameter. Section apparently nearly circular. The whorls 

 are somewhat closely inrolled, the first three slightly indenting each .other. 

 In the second whorl there are six septa to the inch, and in the third whorl 

 four to the inch, as seen on the median line of the side. The umbilicus is 

 deep, exposing all the whorls to the apex. Siphuncle and surface unknown. 

 The specimen is a fragment consisting of a little more than three whorls, 

 and as there are traces of the septa visible to the extremity or where the 

 last whorl is broken off, it is evident that no part of the chamber of habi- 

 tation is preserved. In the centre of the umbilicus there is a space eight 

 lines in diameter, in which no indication of structure is seen, and is taken to 

 be the size of the first whorl. The second whorl, commencing with a dorso- 

 ventral diameter of five and a-half lines, enlarges to eleven lines in making 

 one complete turn. The third whorl, commencing with a diameter of 

 eleven lines, enlarges to thirty-three lines. Diameter of the whole 

 specimen, consisting of about three and one-eighth whorls, six inches. 



This appears to be quite distinct from all those described in the preced- 

 ing pages. It approaches, in form, N. tyrans of the Chazy limestone, 

 but is more compactly inrolled. 



Locality and Formation. — Mingan Islands ; Calciferous formation. 

 Collector .—3 . Richardson. 



