CIDARID^. — PURPLE EGG-URCHIN. 177 



ratus, known by the fanciful appellation of ' Aristotle's 

 lantern/ "* 



In heraldry we find, according to Mr. Moule, that the 

 Echinus is borne, the arms of the Alstowne family being 

 yules, three sea-urchins in pale argent ; and those of 

 Alstanton, azure, three sea-urchins argent. The shells 

 of Echinus sphcerea, the common sea-egg, are often used 

 for making emery cushions, cases for yard measures, 

 and other toys. 



Pennant mentions sea-eggs being used for food in 

 many parts of England ; and Mrs. Gatty, in ' Old Folks 

 from Home,' if I remember correctly, states that Echinus 

 lividus, or "purple egg- urchin," is eaten on the west 

 coast of Ireland. It is one of the burrowing species, 

 and lives in holes formed by it in the rocks. Mr. W. 

 Thompson informed Professor Forbes, that he had 

 seen it in abundance in the South Isles of Arran. "It 

 was always stationary, the hole in which it is found 

 being cup-like, yet fitting so as not to impede the spines. 

 Every one lived in a hole fitted to its own size, the little 

 ones in little holes, and the large ones in large holes ; 

 and their purple spines and regular forms presented a 

 most beautiful appearance, studding the bottoms of the 

 grey limestone rocks' pools."t 



At the Museum of the Jardin des Plantes, at Paris, I 

 have seen specimens of this Echinus in a block of sand- 

 stone from the Baie de Douarnenez, in Finisterre ; also, 

 specimens of Echinus perforans in granite rock from 

 the Bay of Croisic. How these animals bore into such 

 hard substances is still a question; it is supposed by 

 some that they first perforate with their teeth, and 

 then soften the rocks by some secreted solvent. J 



* Forbes'B ' British Star-fishes,' p. 154. + lb. p. 170. % lb. p. 111. 



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