62 
This shell agrees, in some of its anomalies, with the description of 
Voluta depressa, Lam. ; but it seems to differ from that shell, which, 
however, I have not seen. 
XXVII. Strombus. A slightly ventricose univalve, terminating at 
its base in a short notched or truncated canal. The lip enlarges with 
age, appearing like a plain, entire, and single lobated wing, with a 
groove in its lower part. This last circumstance appears to be parti- 
cularly characteristic of this genus. 
Lamarck describes but one shell of this genus as found in the 
neighbourhood of Paris. This is Strombus canalis, resembling, in 
many respects, the rostellaria Jissurella of the next genus, but 
differing from it in having a groove on its right edge. 
Fossil shells of this genus are very rare. Some of extraordinary 
preservation have, however, been found in the mountains of Arragon. 
In the Veronese also are found small alated strombi, in very excellent 
preservation, although very much changed in colour, apparently from 
ferruginous impregnation. 
XXVIII. Pterocera. A ventricose shell, terminated inferiorly, by 
an elongated canal ; the right edge dilating with age into a digitated 
wing, and having a sinus towards its base. 
Strombus lambis, Linn, is the type of this genus, none of the 
species of which are known to me to exist in a fossil state. 
XXIX. Rostellaria. A slightly turreted or fusiform univalve, 
terminating at its base in a lengthened canal, similar to a sharp beak. 
The lip whole or dentated, and dilated with age ; with a groove con- 
tiguous to the canal. 
This genus is distinguished by the sinus of the inferior part of the 
right edge being contiguous with the canal in the beak of the shell, 
which does not take place in the Pterocerce and Strombi. 
The most remarkable fossil shell of this genus is, Rostellaria ma~ 
croptera, Lam. ; Strombus amplus, Brander. Brand. Foss. p. 34, 
Plate VI. Fig. ^6 ; found in Hampshire, and at Courtagnon, St. Ger- 
