THE, CRETACEOUS, PERIOD: Py fe | 
The Univalves (Gasteropods) of the Cretaceous period are 
not very numerous, nor particularly remarkable. Along with 
species of the persistent genus Pleurotomarza and the Meso- 
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Fig. 199.—Hippurites Toucasiana. 
A large individual, with two smaller 
ones attached to it. Upper Cretace- Fig. 200.—Voluta elongata. 
ous, South of Europe. White Chalk. 
zoic JVeringa, we meet with examples of such modern types 
as Turritella and Vatica, the Staircase-shells (So/arium), the 
Wentle-traps (Sca/aria), the Carrier-shells (Phorus), &c. To- 
wards the close of the Cretaceous period, and especially in 
such transitional strata as the Maestricht beds, the Fax6e 
Limestone, and the Pisolitic Limestone of France, we meet 
with a number of carnivorous (“ siphonostomatous”) Uni- 
valves, in which the mouth of the shell is notched or pro- 
duced into a canal. Amongst these it is interesting to 
recognise examples of such existing genera as the Volutes 
(Voluta, fig. 200), the Cowries (Cyfrea), the Mitre-shells 
(Mitra), the Wing- shells (Stvombus), the Scorpion - shells 
(Lleroceras), &c. 
