62 



base in a short notched or truncated canal. The lip enlarges with age, 

 appearing like a plain, entire, and single lobated wing, with & groove 

 in its lower part. This last circumstance appears to be particularly cha- 

 racteristic of this genus. 



Lamarck describes but one shell of this genus as found in the neigh- 

 bourhood of Paris. This is Strombus canalis, resembling, in many re- 

 spects, the rostdlaria fisturella 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 pre- 

 servation 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, termi- 

 nating at its base in a lengthened canal, similar to a sharp beak. The 

 lip whole or dentated, and dilated with age ; with a groove contiguous 

 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 Pterocera and Sirombi. 



The most remarkable fossil shell of this genus is, Rostellaria macroptera, 

 Lam. ; Styombus ampins, Brander. Brand Foss. p. 34, PL 6, Fig. 76 -, 

 found in Hampshire, and at Courtagnon, St. Germain en Laye, &c. in 

 France. This large and handsome fossil, so finely displayed in Bran- 

 der's work, is remarkable for the size of its right lip, which is formed 

 into a wide, round, and rather thin wing, extending from the canal at 

 the base, over the body of the shell and a great part of the spire. AH 



