ROSTELLARIA. 



Shell turrited or fusiform^ the spire in all cases much 

 longer than the aperture ; and^ as we believe^ always 

 acute at the base. Aperture oblongs its superior extre- 

 mity extended into the form of an elongated, very narrow 

 canal, which runs up, sometimes to the top of the spire, 

 and then frequently turns downwards on the other side 5 

 its inferior extremity also forming a more or less length- 

 ened canal, pointed at the base. Outer lip more or less 

 dilated with age, entire, or dentated at its lower edge, or 

 divided into several fingers. The upper volutions of the 

 Rostellariae are generally longitudinally grooved, parti- 

 cularly of such as have their outer lips either entire, such 

 as R, Columbaria, or dentated, as R, Fusus: but they are 

 carinated or tuberculated in those that have the outer 

 lip divided into fingers, such as the Pes-Pelecani : and 

 these have as many rows of tubercles, or the same num- 

 ber of carinae on the lower volution, as there are digita- 

 tions to the outer lip. The lower extremity of the outer 

 lip is sinuated close to the pointed canal, and by this 

 character, the RostellaricB are distinguished from the 

 Stromhi and Pterocerata, in both of which, this sinus or 

 emargination does not nearly approximate to the lower 

 canal ; this character, moreover, is the only one that 

 separates Pes-Pelecani from Strombus, and compels us 

 to place it with Rostellaria, as we think contrary to its 

 natural affinity. 



The Rostellarise are naturally covered with a thin 

 horny epidermis, and they have a thick horny operculum 

 which is only attached to the foot of the animal by about 

 half its surface, it is of an oblong shape, rounded at one 

 end, and pointed at the other. Only a small number of 

 recent species are known, one of which is a remarkable 

 shell, on account of its scarcity and the extraordinary 

 length of the lower beak; it is the Strombus Clavus, 

 Gmel.; Rost. rectirostris. Lam. The R, Pes-Pelecani is 

 the only one found on our coasts. Fossil species are more 

 numerous, they are mostly remarkable shells; several 

 with entire, but sometimes excessively dilated outer lips 

 are found in the London Clay; of these the Strombus 

 latissimus of Brander, is a distinguished fossil; other, 

 more strombiform species occur in the Green Sand. The 

 Calcaire grossiere of Paris, and the tertiary beds of Bor- 

 deaux and Italy, furnish several species. 



