118 



reflected, and is continuous above with a flat, expanded, semiovate callus, 

 which spreads over nearly the whole of the columellar side of the mouth 

 and sometimes covers a small portion of the last whorl but one. At the 

 junction of the outer with the inner or columellar lip there is a rather 

 deep and sub-angular notch or " insinuation," whose centre is exactly in 

 a line with the suture. There are three large, prominent, oblique, spiral 

 plaits on the columella, which are parallel with each other, and about 

 three lines apart at their summits. The upper or posterior plait is placed 

 near the middle of the aperture, on its inner side, and the lowest, which 

 is the least prominent of the three, is situated half way between the 

 posterior plait and the base of the shell. On the body whorl the surface 

 markings consist of eighteen or nineteen revolving raised lines or narrow 

 ridges, which are interrupted and made nodulous by their being crossed 

 by obscure and low, but rather broad, transverse folds, and coarse striae 

 of growth. 



F. Navarroensis is probably only a varietal form of the Valuta elongaia 

 of D'Orbigny and other authors, which tStoliczka places in Schumacher's 

 subgenus Fulguraria. The«difi'erence between the two nominal species 

 practically amounts to this, that in some specimens of F. elongata the 

 body whorl is more constricted j)Osteriorly than it is known to be in F. 

 Navarroensis, and that the transverse ribbing or plication of the surface 

 is strongest in the former. A glance at Stoliczka's illustrations of Indian 

 examples of F. elongata, however, will be suificient to shew that these 

 distinctions are not much to be relied upon as affording good specific 

 characters. Nine individuals of this species are represented on Plate 7 

 of the second volume of the Paloeontologia Indica, and four of these are 

 not more constiucted near the suture than the Sucia Island specimens of 

 F. Navarroensis are. The insinuations of the striae of growth, too, which 

 Stoliczka says " are inseparably connected with the posterior constriction 

 of the whorls," are very plainly visible in most of the Sucia Island 

 Volutes, and the transverse plications of the sui-face in some Indian 

 varieties of F. elongata, do not appear to be much more strongly marked 

 than they are in average American individuals of F. Navarroensis. 



The name Volutilithes has been used in such a wide sense by recent 

 writers, that it has come to have about the same significance in Paleon- 

 tology as the Linnaean genus Valuta has in Zoology. If used at all, the 

 former name will probably have to be restricted to a group of more or 

 less angular and spinous Eocene species, with feebly developed columellar 

 folds, such as the Voluta spinosa of Lamarck, and the V. luctatrix of 

 BrAnder. Voluta elmgata, V. J!iavarroenns, and a numbeor of closely re- 



