26 THE SEA-SIDE AND AQUAEICTM. 



corpulent Soldier- Crabs. The length of a specimen 

 now before me measures four and a-half inches. It 

 is completely covered on the outside with Barnacles 

 and small Mussels, while the interior is lined with a 

 very delicate zoophytic crust, forming a kind of reti- 

 culated veil, beneath which lie several tubes of the 

 Serpulse. 



Closely resembling this shell in general formation, 

 though of considerably smaller size, is the common 

 Dog- winkle (Purpura lapillus). The colour of this 

 mollusc varies greatly. In some, the prevailing tint 

 is white, in others, yellow or deep orange. Not 

 unfrequently the shell is prettily ornamented with 

 spiral bandings of chesnut or dark brown. No small 



COMMON WHELK (Pwrpura Lapillus). 



interest is attached to this little creature, from the 

 belief that it supplied the purple dye for which Tyre 

 was famous over the world. But here, as elsewhere, 

 we may avail ourselves of the labours of our prede- 

 cessors. A late writer says : 



"The most beautiful dye-stuff of antiquity was 

 the Tyrian purple, so called from the place of its dis- 

 covery and chief manufacture. I should rather have 

 said, perhaps, place of its reputed discovery, for its 



