258 PURPUEIEEEA. 



They may be generally distinguislied by tlie flatness of tbe 

 columellar lip, and by tbe short canal or emargination, which is 

 not reflected or raised, as in Buccinum. The species are very 

 numerous and very variable in form, inhabiting the seas of tem- 

 perate and tropical climates. The animals secrete a purple 

 liquor, which has been used advantageously for dyeing; the 

 origin of the famous Tyrian dye. E-eeve's Monograph contains 

 about 80 species. Ex. P. persicula. PI. xix. fig. 44. 

 PTJEPUEIPEEA. Lam. {Purpura, purple ; fero, to carry.) A 

 family belonging to the second section of Lamarck's order 

 Trachelipoda, the shells of which are described as having a very 

 short recurved, or ascending canal, or else only a notch between 

 the inner and outer lips. The name Purpurifera has been given 

 to the family, because the animals which it includes, and par- 

 ticularly the genus Purpura, contain the colouring matter from 

 which the ancients obtained the well-known splendid purple. 

 This family contains the following genera. 



1. Cassis. Outer lip thick, reflected, denticulated, canal 



turned suddenly over the back ; spire short ; including 

 Cassidea and CyprcBcassis. Pig. 410 to 412. 



2. Cassidaeia. Canal turned gently upwards. Pig. 407, 408. 



3. Okisoia. Inner lip granulated ; canal short. Pig. 409. 



4. Btjccintjm. Outer lip thickened not reflected; canal 



short ; including Cyllene and Phos. Pig. 416, 421, 422, 

 425. 



5. Nasa. The same, with a notch or tooth at the extremity 



of the columella ; including Cyclops. Pig. 423, 424. 



6. DoLiUM. Swelled, grooved spirally; outer lip not re- 



flected. Pig. 420. 



7. PuBPTJEA. Aperture large ; columellar lip flat ; including 



Tritonidea. Pig. 414, 415. 



8. MoNOOEEOS. The same, with a tooth on the outer lip. 



Pig. 417. 



9. CoNOHOLEPAs. Patelliform ; aperture as large as the 



sheU. Pig. 417. 

 10. EiciNULA. Columellar and outer lips granulated, denti- 



