Om the Economical Uses of some species of Testacea. 239 



the description and plate given, he appears to have made use of the 

 common periwinkle (JBuccinum Lapillus, Linn.) for this purpose. 

 On trying the experiment himself, the writer found the color to 

 vary much, and frequently before attaining its final hue. At first it 

 was pellucid and nearly colorless, then became a light green, and if 

 placed in the sun, immediately much darker ; in a few minutes it 

 changed to a full sea green, and after that into a watchet blue ; in a 

 few minutes more it was a purplish red, and after lying ah hour or 

 two became a very deep purple. Further than this the sun did not 

 affect it, but on being washed in soap and water it changed to a very 

 bright and brilliant crimson. When the article dyed with it lay in 

 the sun, it emitted a very strong and fetid smell, as if garlic and as- 

 safoetida were mixed together. More lately a species of shell was 

 used by the Spanish Americans at Nicoya, also for dyeing with, but 

 the cloth thus prepared was so expensive as only to be worn by the 

 nobles.* Among the Romans the royal edicts were frequently 

 signed with this liquor, and it was used as a pigment by artists. 



In common with the rest of the genus, the fish is carnivorous and 

 locomotive, living sometimes in deep water, and sometimes burying 

 itself in the shore, while it is constantly searching for food. The 

 coloring liquor is probably provided as a means of defense to the ani- 

 mal, as the ink of the cuttle fish, or the saliva of the snail ; and 

 although we have never observed the fact in any American or Brit- 

 ish species, the fish when touched is said to have the power of volun- 

 tarily emitting it.f In which case it comes out purple, and of a very 

 rank and offensive odor. If this be so, it must undergo some change 

 in passing through the vein, as when cut out it is white, and long in 

 attaining its purple and final hue. Since the discovery of America, 

 and the introduction of cochineal into Europe, the fish dye has been 

 entirely neglected as an article of merchandise, and is not, that we 

 are aware of, any where used in the present day. 



VII. MuREX Tritonis, (Linn.) — Trumpet Shell. 



This fine univalve is indigenous to most warm climates ; it inhabits 

 the African, American, and Asiatic seas, and is found on the coasts 

 of the islands of the southern Pacific. The only use it appears to 



* Rees' Cyclopaedia. Article Purple Fish. 



t Aristotle, de Hist. Animal, lib. v. cap. 15. Hughes' Nat. Hist, of BarbadoeSj 

 p. 272. 



