340 CRETACEOUS GASTROPODA 
2. NeritiInA (VELATES) DECIPIENS, Stoliczka, Pl. XXIII, Figs. 9-10. 
Nerit. testa transversaliter rotundate-ovata, depressa, levigata, striis increments 
minutis notata ; anfractibus duobus; spira plana, fere obtecta ; ultimo anfractu 
margine exteriore late expanso, labio calloso, convexo, levi, margine interiori 
equaliter crasse dentato. 
A much depressed, transversally broadly ovate shell with smooth surface and 
indistinct, flattened spire. There are generally not more than two whorls present, 
and the spire is sometimes perfectly enveloped. The outer margin of the aperture 
is largely expanded, anteriorly on the internal side slightly thickened and smooth. 
The inner lip is formed by a strong, convex and roundish callosity, which has on the 
internal margin eight equally strong teeth. 
Comparing with our shell young specimens of Velates Schmideliana (see 
Deshayes’ Anim. s. vert. Foss. Paris, edit. I, pt. IT, pl. 18, figs. 1-2), it will be seen 
that the eretaceous species very probably belongs to the same sub-generic division 
of Nerita. This is indicated not only by the envelopment of the spire, the great 
expansion of the outer lip and its flattened margins, but principally by the peculiar 
form of the callose inner lip and its strong and equal dentition, which is perfectly 
distinct from that of any recent Neritine. Our specimens—10 in number and 
the largest not above 15mm. in transversal diameter—may be all young shells. 
Locality —Comarapolliam, in light coloured siliceous sandstone; not very rare. 
Formation.—Arrialoor group. 
LXXVIII. NERITA, Adanson, 1757. 
1. Noeriva pivaricata, d’Orbigny, Pl. XXIII, Figs. 11-12, and Pl. XXVIII, 
Fig. 5. 
1846. Nerita ornata, Forbes, Tran. Geol. Soc., Lond., VII, p. 121, Pl. XIII, Fig. 5 (non idem Sow., Melv.). 
1847. ,,  divaricata, d’Orbigny, Paléont. Voy. Astrolabe, PL IV, Figs. 43-44. 
Nerit. testa transversaliter sub-ovata, sub-globosa, crassa, anfractibus tribus 
composita ; spira brevi, aliquantisper viv elevata ; superficie costulis numerosis 
transversalibus atque antice in ultimo anfractu striis spiralibus decussantibus notata, 
costulis atque striis in speciminibus adultis sepe obliteratis; apertura semilunari, 
angusta, intus valde callosa ; margine labii octo dentibus crassis imstructo, prope recto. 
Transversal diameter of largest specimens about 40 mm. 
This fine species has the same transversally oval shape as the WN. Zekeliana 
from the Alpine Gosau-deposits, but it can be distinguished from it by the transverse 
ribs being somewhat thinner and more numerous. I have already mentioned that 
there have been from Europe and Africa a large number of very similar forms 
described under different names, but they may all prove to belong only to one and 
the same species. Well preserved specimens must, however, be examined before a 
reliable opinion as to their identity can be given. 
Our present species consists of about three vanity increasing volutions, the 
spire being more or less distinct in various specimens. ‘The anterior half of the last 
