86 ROSTELLARIA. PTEROCERA. STROMBUS. 



" The genera are three — 



Rostellaria, \ 



Pterocera, ^ Strombiis, wing-shell. 



Strombus, 



" In the first genus the shells are terminated 

 below by a canal, or pointed beak ; the right- 

 margin entire, or toothed, more or less dilated 

 with age, and having a sinus contiguous to the 

 canal. There is a specimen from our own coast, 

 Rostellaria pes-pelica?ii, the pelican's-foot : it 

 was Strombus of Linnaeus. (Plate 7-) There 

 are many of this species found in a fossil state. 



^' The Pterocera genus is easily known by the 

 digitated, or fingered, appearance of the right-mar- 

 gin. The greater part of the species become very 

 large. Here we find the scorpion, with seven 

 digitations, from India ; the spider, with the 

 same number, a large and fine shell, also from 

 India. 



" Strombics has a short canal, the right-margin 

 dilated with age into a simple wing, having, at 

 the lower part, a sinus, separated from the canal 

 at the base of the shell. 



" All the species are natives of hot climates ; 

 some attain a very large size, such as S. gigas, 

 so frequently seen in shops, and as ornaments in 

 a room. ^S*. gibberuhis is a pretty little shell ; 

 the white, gibbous whorls render it remarkable ; 



