276 HISTORY OF BRITISH ZOOPHYTES. 



and either white or of a light purple colour. It is seldom 

 more than half an inch in length. 



9. TUBTJLIPORA HYALINA, R. Q. Couch. 



Hab. On Fucus palmatus, Polperro, Couch. 



" Encrusting in small semi-transparent patches of about 

 the diameter of a pea. The cells are distant, erect, ar- 

 ranged in one or two rows round a plain centre." 



Genus II. DIOSTOPORA, Lamouroux. 



Gen. Char. Polypidom calcareous, encrusting, undefined; the 

 cells alternating, tubular, horizontal, immersed, with a raised 

 circular aperture. Johnston. 



1. DIASTOPORA OBELI A, Dr. Fleming. 



Hab. Scarborough, Mr. Bean; Berwick Bay, Dr. John- 

 ston; Cornwall, Mr. Couch; Devonshire, Mrs. Gulson and 

 Mr. Peach ; Salcombe Bay, very fine on scallop-shells, Rev. 

 T. Hincks; Yorkshire coast, Mrs. Gatty; Irish coast, Mr. 

 W. Thompson; off Sana Island, Mr. Hyndman; island 

 of Tiree, Hebrides, D. L. 



The crust is thin, and adheres so closely to the shell on 

 which it grows, that it cannot be removed from it without 

 breaking it in pieces. The cells are pretty much immersed ; 



