PURPURA. 281 



According to him it deposits its spawn all the year 

 round, but more actively from January to April. Spawn 

 which he collected in January 1843 was hatched four 

 months afterwards ; he took 47 fry from a single cap- 

 sule. They soon began to assume the peculiar habit of 

 their parents, " by getting out of the water, where they 

 would remain for hours, answering to the period of the 

 ebb and flow of the tide." Cailliaud counted 245 cap- 

 sules which had been produced by a single Purpura 

 about the same time ; each capsule contained from 16 

 to 28 perfect embryos [making therefore an average 

 total of 5390] : they were hatched in turn by the parent, 

 which (as he supposes) thus not only supports them by 

 her nutritious moisture, but protects them against 

 accidents. I have only seen the Purpura covering with 

 her shell the egg-cases while they were being laid. M. 

 Cailliaud adds that some of the inhabitants of St. Michel- 

 Chef- Chef eat this shell-fish after the spawning-season. 

 It does not seem to be anywhere else an article of food — 

 although our remote ancestors were probably less fasti- 

 dious in their tastes; for the shells are found in the 

 refuse-heaps or kitchenmiddens of ' Picts ' houses' near 

 Wick, mixed with shells of the common periwinkle, and 

 occasionally of the limpet and mussel. Within the period 

 of civilization this mollusk has been made useful in 

 another way ; and a great deal has been published con- 

 cerning the purple dye which is yielded by our Purpura, 

 as well as by that of the Greeks and Romans. The Vene- 

 rable Bede mentions it, in terms of admiration, in his 

 Ecclesiastical History of England : as to its permanency, 

 he says, " quo vetustior, eo solet esse venustior." The 

 subject has been since discussed, in both an economical 

 and philosophical point of view, by a crowd of writers, 

 English, French, Norwegian, Spanish, Italian, German, 



