280 HISTORY OP BRITISH ZOOPHYTES. 



more conspicuous than the preceding species, and can 

 scarcely escape observation. It adheres, also, more firmly 

 to the shell on which it grows, the basis spreading beyond 

 the cells, and the cells are unmarked with granules. 



3. ALECTO DILATANS, W. Thompson. 



Hab. Island of Sana, dredged by Mr. Hyudrnan ; coast 

 of Northumberland, Prof. W. King ; dredged off the Mull 

 of Galloway, in from 110 to 140 fathoms, by Professor E. 

 Forbes ; island of Islay, Lady Emma Campbell. 



This is a pretty species, as may be seen in Dr. Johnston's 

 plate xlix. fig. 5, 6. It creeps along on the surface of 

 bivalve shells in a branching manner, each branch being 

 fullest at the top, as in the preceding species. The cells are 

 tubular, and a good deal immersed ; they are also marked 

 with granules. Dr. Johnston says that he has sometimes 

 thought that it might be a state of Diastopora obelia. We 

 have seen it in circumstances which thoroughly convinced 

 us that it was quite distinct from D. obelia. Some time 

 ago my friend the Rev. Mr. Nicol, of Coll, sent me some 

 valves of Pinna ingens, dredged from deep water by the 

 fishermen of that island. I valued the Pinna, but I prized 

 much more the zoophytes that were parasitical upon it. 

 There were various fine Legralice, some of them in the 



