Coralline^.'] melobesia. 279 



conical, sessile capsules (cevamidia) scattered over the surface of 

 the frond, and containing a tuft of transversely parted oblong 

 tetraspores. — Name from one of the Sea Nymplis of Hesiod. — 

 Harvey. 



1. Melobesia polymorpha, Linnmis. 



Hab. On submarine rocks and in quiet bays. AVe have 

 dredged it in Lamlash Bay^ where there are extensive beds 

 of it, at the depth of several fathoms. Similar beds are 

 found at Hothesayj and in Loch Fyne. 



It is very hard and very diversified in form, as the specific 

 name implies. Eay says that it is dredged out of Falmouth 

 Harbour to manure their lands in Cornwall ; and Mr. W. 

 Thompson informs us that it is dredged in Bantry Bay for 

 the same purpose. From Professor John Fleming we learn 

 that it is so abundant in Orkney as to warrant the conclusion 

 that it might be advantageously employed for agricultural 

 purposes and for building, especially as limestone is scarce 

 in Orkney, and generally of bad quality. Dr. Walker, in 

 his Essays, says, " Of the cathedral of Icolmkill (lona), 

 the cement is so strong that it is easier to break the stones 

 than to force them asunder. It is of lime that has been 

 calcined from sea-shells, and formed into a very gross 

 mortar, with coarse gravel, in a large proportion, and a 



