[NVEETEBRATE PALEONTOLOGY. -505 



0.62 inch ; slopes of spire a little convex, with a divergence from the apex 

 of about 38°. 



Of tlie little revolving bands, which are narrower than the spaces between, 

 some seven to eight may be counted on the penultimate volution, where they 

 are, like those above, usually of uniform size. On the body-volution, there 

 is generally a smaller band, or line, between each two of the larger ; and some- 

 times, especially on the lower half of this volution, those of this smaller series 

 become nearly or quite as large as the others. On well-preserved specimens, 

 there may sometimes be seen, by the aid of a magnifier, traces of very 

 obscure, minute striae, between the revolving bands. These very minute 

 stria?, however, are more generally entirely obsolete. Notwithstanding the 

 strong sculpturing of this shell, the entire surface, both upon and between 

 the folds and revolving bands, has a peculiar shining, polished appearance. 



The vertical folds, or costae, are slightly arched, and although not wide, 

 are distinctly defined, especially on the volutions of the spire, where they 

 equal the spaces between, and number about eighteen to each turn. On the 

 body-volution, they become more irregular, or often nearly obsolete toward 

 the aperture, and below the middle. 



The original type-specimen of Buccinum ? vinculum, believed to be 

 identical with the shell here described, is small, and has its beak and 

 upper volutions broken away, and its aperture not exposed ; consequently, 

 its generic characters could not be clearly determined. The specimens 

 now before me, however, from the same locality and position, are larger 

 and in a much better condition, showing not only the entire form and orna- 

 mentation, but the aperture also. These, as may readily be seen from the 

 figures, certainly do not belong to the genus Buccinum, but agree much more 

 nearly with Fusus, to which we at one time removed the species. The pres- 

 ence of the internal varices, however, shows that this shell cannot belong 

 properly to Fusus, but that it has apparently nearer relations to Tritonium. 



By comparing our figures with those of the original type-specimens of 

 Buccinum I vinculum and Fusus Shumardii, Hall and Meek, it will lie seen 

 that they represent an almost exactly intermediate form between the two. 

 This fact, and the exact agreement of the ornamentation of these shells, has 

 sometimes led me to suspect that B. I vinculum and Fusus Shumardii may 

 possibly have been founded on extreme varieties of one species, especially 

 as the type-specimen of the former is so imperfect as not to give a clear idea 

 39 h 



