282 HISTOEY OF BEITISH ZOOPHYTES. 



Hab. Very common on seaweeds, such as Dasya coccinea 

 and Delesseria sanguined ; common also on other zoophytes. 



This ivory-tufted coralline, though generally as white as 

 ivory, from which it takes its specific name, is occasionally 

 tinted with rosy-red. It is much branched, nearly half an 

 inch in height ; cells in two rows, sometimes nearly alter- 

 nate, at other times opposite. Pear-shaped vesicles are 

 scattered over the branches, finely granulated. 



2. CRISIA DENTICULATA, Dr. Fleming. 



Hab. On seaweeds and corallines, like the preceding, but 

 not nearly so common. It is not rare on the coast of Ayr- 

 shire, but it is smaller in size than specimens from England 

 and Ireland. The finest specimens I have are from Miss S. 

 Beever, and from Mr. Tumanowicz, Hastings. They are 

 above an inch in height, and as much in breadth. Its 

 larger size and stouter texture, and still more its black 

 joints, which give it a spotted appearance, enable even the 

 naked eye to distinguish it from the preceding ; with which, 

 nevertheless, it was confounded, till Prof. J. Fleming 

 pointed out the difference. 



3. CRISIA ACULEATA, A. H. Hassall. 



Hab. Kingston Harbour, Mr. Hassall ; near Lame, Mr. 

 B. Paterson ; Ballantrae, Ayrshire, Mr. W. Thompson. 



