465 



rugineo strigata, strigis ad umbilicum continuis ; margine interno 

 umbilico albicante, externo ferruginea. 



In form this species most nearly resembles N. ambiguus, though 

 in its colouring it is like N. Pompilius. Its large umbilicus, with 

 a rounded margin, at once distinguishes it from both. 



5. Nautilus stenomphalus (pi. xcvii. f. 3), nobis. 



Testa suborbicularis, subventricosa, utrinque umbilicata, um- 

 bilico angusto, margine umbilici subinterno leviter angulato ; 

 pallescens, postice radiatim ferrugineo strigata, strigis ad dorsum 

 contiguis, ad centrum discontinuis ; apertura rotundato-cordata. 



Nearly similar in shape to JV. macromphalus, but distinguished 

 by the smallness of its umbilicus, the subinternal margin of which 

 is slightly angular : in colouring it is like N. ambiguus. 



NAUTILUS. 



EXPLANATION OF PLATES XCVII. AND XCVII1. 



Fig. 





1. N. 



pompilius, sp. 1. 



2. .. 



ambiguus, 2. 



3. .. 



stenomphalus, 5. 



4,5. .. 



macromphalus, t 



6. .. 



pompilius, I. 



7. .. 



umbilicatus, 3. 



