OF CONCHOLQGY. 



18$ 



Figure 6 gives one central with the first two laterals, one of the 

 intermediate teeth, and the three extreme marginals. Figure 8 

 is drawn from a different part of the membrane, apparently its 

 most developed portion. It gives a group of centrals and lat- 

 erals in which an enormous development is seen of the median 

 cusp of the central tooth. 



Nanina cultrata, Gould, received from Mr. J. Harper Pease. 

 The lingual of this species has the same general characteristics 

 as that described above. The centrals and laterals, however, 

 are more slender ; there are six of the latter. The marginals are 

 more numerous in this species ; those on the extreme edge of the 

 membrane are not only bluntly bifid at their extremity, like all 

 the inner marginals, but also bear upon the lower edge of their 

 recurved portions several blunt notches, giving the tooth a multi- 

 fid appearance. 



