GENERA OF SHELLS. 85 



PTEROCERA. Shell ovate oblong, ventricose, 

 terminated inferiorly by an elongated canal. 

 Lip dilating by age into a digitate wing, and 

 having a sinus towards the base. Spire short. 

 The canal at the base is not shortened and truncated 

 as in the strombi, but elongated and caudiforrn, attenu- 

 ated towards the extremity and frequently closed. The 

 sinus is not contiguous to the body of the shell as in 

 rostellaria. The strornbi differ only in wanting the 

 digitations of the dilated wing and by their short 

 canal. 



P. truncata, lambis ; millepeda, pseudo scorpio, scorpio, 

 aurantia, chiragra. 



STROMBUS. Shell ventricose, terminating in 

 a short emarginate or truncate canal. Lip 

 dilating by age into a simple wing, lobed or 

 crenate superiorly, and having a sinus distinct 

 from the canal or ernargination of the base, 

 inferiorly. 



Distinguished from pterocera by the digitations of 

 the right lip and by the canal being short, truncated or 

 notched : from rostellaria by the sinus being separated 

 from the canal by a portion of the lip. 



S. gigas, accipitrinus, latissimus, tricornis, gallus, bitu- 

 berculatus, cristatus, dilatatus, bubonius, lentiginosus, auris 

 Dianae, pugilis, pyrulatus, gibberulus, luhuanus, Mauritianus, 

 canarium, Isabella, vittatus, epidromis, columba, succinctus, 

 troglodytes, tridentatus, urceus, plicatus, floridus, papilio, 

 lineatuSj marginatus ? turritus, cancellatus, canalis. 



