170 



CIDARITES. 



rocks, and which are never left entirely dry, these ledges 

 are perforated by the Echini ; and I have seen thousands 

 of them lying in these cavities side by side. The largest 

 which I saw thus embedded were about three inches in 

 diameter, and the few that I perceived out of their nidi. 

 All that I thus observed were of the same species. The 

 fishermen sometimes take the common Echinus in their 

 lobster-pots ; but these are never lodged in the rock. I 

 have been lately informed that they lodge in a similar 

 manner in the rocks about Berehaven and Bantry in the 

 west of our county (Cork).'''' 



Mr. W. Thompson informs me it is gregarious, and was 

 seen abundantly in rock pools at low water by himself and 

 Mr. Ball when visiting the south Isles of Arran in 1834. 

 It is 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. The same gentleman states that the coral 

 lining the cavities, alluded to by Mr. Bennett, is the com- 

 mon Millepora. I saw it under similar circumstances in 

 Donegal Bay, in August 1840. 



Mr. Ball has paid much attention to this animal at the 

 request of the British Association, with a view to discover 

 its mode of boring, though as yet without conclusive 

 results. He brought from Galway some masses of lime- 

 stone with the animals alive in situ. " These," Mr. Ball 

 says, " I deposited in various positions at Kingston, some 

 in baskets, others amongst the rocks, and the remainder I 

 threw out into the harbour ; all that I could again visit 

 had died, but as some may have survived it may be well 



