308 CRETACEOUS GASTROPODA 
smooth inner lip moderately thickened, simply curved or slightly twisted, not toothed ; 
columella excavated ; the recent species are usually white. Though the authors of 
the Zoology of the ‘ Astrolabe’ first pointed out the differences between the genera 
Velutina and Vanikoro, they were not quite certain whether a generic separation 
of the two was really necessary. In reality they only intended to propose the name 
Vanikoro for the peculiarly cancellated species of Velutina. The generic distinctions 
of these from true Velutine, however, have been already in 1830 confirmed by 
Deshayes, and the propriety of the former name as having generic value acknow- 
ledged. The same was done by Gray in 1840, and reference was made to the 
anatomy of the animal as illustrated by Quoy and Gaimard. It is therefore quite 
clear, that the name Vanikoro has priority before Narica, which was, on the 
authority of Recluz, introduced by D’Orbigny only in 1841. 
H. and A. Adams quote twenty-six recent species of Vanikoro, which number 
was lately increased by the researches of Carpenter, A. Adams, Deshayes and 
others to about thirty-two. The genus appears to be also numerously represented 
in former geological periods. Comparatively only few tertiary species are known ; 
the cretaceous forms seem to be, however, more numerous. Pictet and Campiche 
(Mat. p. 1. Pal. Suisse, 8me. Ser., p. 400,) mention four species, from which the 
Nat. carinata, Sow., may be excluded, because the form and the great thickness of its 
shell makes it more probable that the species is a Fossar (fam. Lirrorrips, vide 
p- 261). To the three other remaining species may be added Nat. crenata, Zek., 
from the Gosau-deposits (Sitz. Akad., Wien, 1865, LIT, Stoliczka, Revision. etc., 
p. 47), Naticella Strombeckii, Miller (Aach. Kreidef., II, p. 16, pl. 3, fig. 20), very 
likely also Nat. Klipsteini, Mull. (bid., p. 14, pl. 5, fig. 1), and perhaps many 
others. In fact of all the species, quoted by Pictet and Campiche (loc. cit., 
pp. 408-409,) under the name of WNeritopsis, the larger number probably belongs 
to Vanikoro, as I shall mention subsequently. Meek has in his Check list of creta- 
ceous and jurassic fossils, p. 18 (Smithson. Mise. Coll. n. 177,) a Vanikoro ambigua, 
Meek and Hayden (Natica id. olim) from N. America. 
It is not improbable, that the greater portion of the jurassic and triassic species 
of Neritopsis also belong to Vanikoro, as certainly do nearly all the species described 
by Miinster and Klipstein from St. Cassian under the name of Naticella. In the 
South-Indian eretaceous deposits only one species has yet been found, the VY. munita, 
Forbes, sp. 
2. Naticodon, Ryckholt, 1847 ? (Mélanges pal., 1852, part I, p. 75,) has the 
general globose form of Vanikoro, but the inner lip is usually thickened and always 
provided with some kind of a tooth ; the columella is either slightly hollowed out or 
solid ; the surface smooth or ornamented with various spiral or transverse strie. 
This genus has been proposed for a number of paleeozoic species and, although 
not accepted by the larger number of conchologists, it appears to be a good genus, 
which ought to be classed in the family Vanzxorip#, forming a connecting lnk 
between Vanikoro and Neritopsis, the former of which has the columellar lip 
smooth, the latter is insinuated in the middle, or provided with two strong teeth, 
