rjQ Mr. Bennett on a peculiar Property 



the present notice appears to be the Echinus saxatilis of Linnœus ; 

 but the character assigned to this species by that distinguished 

 naturalist is so indefinite as to prechide the possibility of cer- 

 tainty on this point. It however coincides precisely with the 

 description given by Leske of his Cidaris rupestris, and with 

 Lamarck's specific character of his Echinus lividus ; both of 

 these authors (the latter Avith a mark of doubt) referring to this 

 species of Linnanis as synonymous with theirs respectively. The 

 appositeness of the trivial names both of Linnaeus and of Leske 

 to the habitat of the animal in question, might lead to the 

 suspicion that they were acquainted with the property noticed 

 above : but there is no reference in either of them to any au- 

 thor by whom it has been mentioned. Rumphius, indeed, de- 

 scribes the Echinus saxatUis as inhabiting " the holes and cavi- 

 ties of corals, in which they sometimes grow to such a size that 

 it is impossible to pull them out." But these words evidently 

 imply his opinion that it sought holes previously formed, in 

 which it increased in bulk ; and do not even hint at the con- 

 clusion, that itself formed and enlarged the cells in which it 

 dwelt. 



Whether the species of Echinus described and figured by 

 Rumphius, and referred to by Linnreus as synonymous with his 

 £. saxatilis, be identical with the one which inhabits the western 

 coasts of Ireland, may probably, on account of their geographi- 

 cal distribution, be regarded as doubtful, the former having 

 been discovered in the Indian Seas. The species of this genus 

 are, however, so difficult to determine, and so little understood, 

 that I will not at present venture to decide upon this question. 

 If not identical, they are at least analogous ; and I may mention 

 as a fact bearing upon this point, that I have lately seen a spe- 

 cimen of Echinus, brought by Captain King, F.L.S., from New 



Holland, 



