ALATID.E. 473 



of retractile. It is simply cloven as in lanthina and Natica, 

 the cleft being rather within the margin of the buccal disk, 

 and provided with the precise attenuated corneous plates and 

 short tongue of the typical proboscis of the Murex undatus. 

 But if malacologists think that what I have stated is not 

 tenable, I will, though my opinion is fixed, abandon this 

 view ; I can well afford to do so, as I have in the shell, 

 the animal, and its habitudes, more than sufficient to con- 

 vince naturalists of the true position of the Rostdlaria pes 

 pelecani. As regards the shell, the alated processes are 

 altogether analogous to the exotic Rostellariee and Strombida, 

 which no one disputes being peculiar developments of the 

 Muricidce. The canal of the shell also at the outer lip 

 side of the beak, or axial process, if viewed properly, that 

 is, with the edge to the observer, is as well marked as in 

 those genera ; and in adult shells the outer lip has a long- 

 vertical row of the same characteristic plicae that are seen in 

 the Marginella lavis, the only other British mollusk I can 

 recollect that has them, another strong, I may say con- 

 vincing, proof that the so-called Aporrha'is pes pelecani is a 

 Muricidal animal. 



As regards the animal, the operculum is absolutely Muri- 

 cidal, and I challenge the most acute observer to distinguish 

 between it and that of a Murex Turtoni of the same size. 

 As for the flimsy objection of the pedicles of the Strombida 

 being peculiar, they are nothing more than typical specific 

 variations. 



I will now allude to the locomotive habitudes of the 

 " RosteUaria pes pelecani"; they are most singular, and the 

 concordance in that respect with the exotic Strombidte men- 

 tioned by Quoy and Gaimard, is perfectly irresistible as to 

 family identity. M. Deshayes, speaking of these gentlemen, 

 observes : 



" On sait depuis eux que le pied de ces mollusques " (Rostel- 

 laria and Strombus) " n'est plus propre a la reptation, et que 

 1'animal, pour changer de place, est oblige de sauter, en ap- 

 puyant sur Fextremite du pied qui porte Popercule." 



