238 NATURAL HISTORY OP 



Zooecia on one side only. 



5. F. CAEBASEA, E. and 8. Plate XIX. fig. 4. 



Carbasea papyracea (Gray), C. papyrea [BusJi, Aid., 

 McA.), F. voile (DeB.), F. papyrea (Smitt), Semiflustra 

 carbasea {D'Orh.). 



Hab. : Aberdeen (Skene), Durham coast [Hogg), 

 Berwick coast (G. J.), Stonehaven {Lady Keith Murray), 

 Newhaven {D.Z.Jun.), Filey {T.H.). 



This specieSj first described by Ellis and Solander 

 (N. H. Z., 14) under the name of the " Lawn Sea Mat," 

 is easily distinguished from the other Flustrce by having 

 cells on one side only, which cells are larger than in 

 any of the other species^ and are egg-shaped at the top, 

 and without spines. It grows to a height of 2 or 3 

 inches, and is broad, and of a yellowish-brown colour. 



Dr. Grant has calculated that " a common specimen 

 of this zoophyte contains more than 18,000 cells.''^ 



FAMILY VIII. MEMBRANIPORID^. 



Zoarium calcareous or membrano-calcareous, incrust- 

 ing (so far as British species are concerned). Zooecia 

 forming an irregular continuous expansion, or in linear 

 series, loith raised margins, and more or less membrana- 

 ceous in front. — T. H. 



Genus I. Membranipora, De Blainville. 

 Zoarium incrusting. Zooecia quincuncial, or irregu- 

 larly disposed, occasionally in linear series ; margins 

 raised; front depressed, wholly or in part membrana- 

 ceous. — T. H. 



With a memhranous front ivall. 

 1. M. Laceoixii, Audouin. 



