PURPURIFERA. 241 



Proceedings for 1841, and an illustrated monograph of the whole 

 genus is published in the Thesaurus Conchyliorum, Part I, by the 

 Author. It may be observed that in one of the new species, the 

 notch in the peritreme almost disappears, leaving a very slight 

 sinus. Fig. 524, 526, 527, 528. 



PURPURA. Auct. ( (< The shell-Jish from which purple is taken" 

 Plin.) Fam. Purpurifera, Lam. Entomostomata, Bl. — Descr. 

 Oval or oblong, thick ; spire for the most part short, sometimes 

 rather longer ; external surface generally sulcated, granulated, 

 tuberculated or muricated ; aperture long, oval, somewhat dilated, 

 emarginated anteriorly ; outer lip crenated, acute ; columella 

 flattened; operculum horny, with the nucleus lateral, thin towards 

 the columella. — Obs. True Purpurse to be found in the Lamarckian 

 genera Buccinum, Ricinula, and others. They may be generally 

 distinguished by the flatness of the columellar lip, and by the short 

 canal or emargination, which is not reflected or raised, as in Buc- 

 cinum. The species are very numerous and very variable in form, 

 inhabiting the seas of temperate and tropical climates. The 

 animals secrete a purple liquor, which has been used advantageously 

 for dyeing ; the origin of the famous Tyrian dye. Fig. 414, P. 

 persica. 



PURPURIFERA. Lam. (Purpura, purple ; fero, to carry.) A 

 family belonging to the second section of Lamarck's order Trache- 

 lipoda, 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 particularly 

 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 Cctssidea 

 and Cijprcecassis. Fig. 410 to 412. 



2. Cassidaria. Canal turned gently upwards . Fig. 407, 408. 



3. Oniscia. Inner lip granulated ; canal short. Fig. 409. 



R 



