FAMILY 9. ALATA. 199 
and included three genera, Strombus, Rostellaria and Pterocera. The 
genus Struthiolaria, which Lamarck referred to his family of ‘‘ Les Cana- 
liferes,” has, however, been very properly added by Deshayes, and we 
think that the removal is one that cannot fail to be appreciated. De Blain- 
ville introduces a very different arrangement of these genera, and it is 
one which seems utterly at variance with their natural characters. The 
genus Rostellaria he assigns to his family of the Siphonostomata, be- 
tween Pleurotoma and Fusus, and the Struthiolarié are included with the 
Tritones in the same family ; whilst Strombus is arranged, together with 
the genus Conus, in another family, the Angyostomata, on account of an 
affinity which he attributes to these genera because their shells somewhat 
resemble each other when young. The peculiarity just alluded to in the 
lip of the Alata, is that it is not expanded at different periods of growth 
as in the Murices, so as to leave a number of external varices, but only 
on arriving towards maturity; and it is often enlarged so as entirely to 
cover the spire, extending in many instances into a number of canalicu- 
lated claws or digitations. Another character, which may be accounted 
of importance, is the constant appearance of a sinus or indenture in the 
lower part of the lip near the basal canal, and some species are remark- 
ably characterized by their having a deep canal on the upper part of the 
shell running from the aperture nearly to the top of the spire. 
The family of the Alata includes four genera, as follows : 
STRUTHIOLARIA. PTEROCERA. 
RostELLARIA. SrrRoMBUS. 
STRUTHIOLARIA, Lamarck. 
Testa oblongo-ovata, spira acuminata, apice subobtuso ; apertura oblique 
ovata ; columella incrassata, polita, in canalem brevissimum, ob- 
tusum, desinente; labro incrassato, sinuoso, sinu subindistincto, 
prope ad canalem instructo. 
