EXPLANATION OF PLATE XLIX. 



Atcrta Vanuxemi Conrad (p. 287). 



Figs. 1. Profile view showing the inside of a septum, the two sinuses formed by the spire, and the 

 broad funnel-formed siphon. 



2. View of the side of a small individual broken so as to show the inner volution, the filling 



of the large siphon and the junction of some of the septa with it. 



3. View of the filling of a single chamber as obtained from a gutta-percha impression in the 



onter cup of the specimen figured on PI. L. Tlie cast straightened somewhat, giving 

 less arcuatiou, but greater length of the ventral portion than should be. The part 

 marked o represents the funnel-formed siphonal depression of the septum. 



Nautilus Cookana Whitf. (p. 285). 



4,5. Dorsal and lateral views of a young specimen of the species, somewhat compressed dorso- 

 ventrally, showing the distant septa and filling of the umbilical cavity. Am. Mus. Nat. 

 History Collection. 



396 



