125 



F. CARNOSA. Encrusting; fleshy, with imbedded remote 

 cells; apertures contracted and armed. 



Flustra bispida, Fleming's Brit. An., p. 537. Fiustra 

 caroosa, Johnston's Brit. Zooph., p. 288, pi. 37, fig. 5. 



Hab. On Fiici, common. 



It is a thick, fleshy encrusting species, of a light brown or 

 cream colour. The cells are imbedded, distant from each 

 other, with contracted wrinkled apertures of a half-moon- 

 sbape, and three or four erect spinous teeth. 



F. TUBERCULATA. Encrusting, calcareous, thin ; cells 

 oval, with a tubercle on the distal, and one on each lateral 

 margin. 



Flustra tuberculata, Johnston's Brit. Zooph., p. 289, pi. 

 34, fig. 9. 



Hab. On stones a few miles from the shore. Polperro. 

 Goran. Mount's bay. 



This is not a rare species, but is to be found encrusting 

 stones at short distances from the shore, from the entrance 

 of Plymouth sound to Faltnoulh harbour 'and Mount's bay. 

 In a living state it is so much unlike t!ie figures and des- 

 criptions given of it, that at one time I considered it a new 

 species, and it was by an examinalion of the dried specimens 

 only that the mistake was discovered. In a living state, 

 its encrusting character resembles the Flustra membranacea, 

 being thin and gauze-like; but it encrusts stones instead of 

 sea weed. It is most commonly found in circumscribed 

 patches varying from a quarter to one inch in diameter. 

 The cells are alternate with stout calcareous rims, and 

 are oval, inclining to a quadrangular or lozenge-shape. At 

 each angle is a large stout tubercle, without any spine or 

 process. It is of a deep flesh red colour. As the cells 

 are alternate, wiih a tubercle on the distal margin, each 

 appears to be surrounded with four, which slightly encroach 

 on the quadrangular diameter. These tubercles are always 

 of a brighter colour than any other part. 



When the specimen is dried, this appearance is consider- 

 ably altered ; the quadrangular shape of the cells is changed 

 into an oval ; the tubercle on the distal margin appears 

 to be considerably above the cell and to stand on a hollow 

 dome; and on each side is a curved process. This species 

 assumes a great variety of forms, from the appearance of 

 this tubercle. In old specimens it is so much injured, and 

 sonietimes so entirely destroyed, that it is diftiouk to re» 

 cognize it; in these states Dr. Johnston's figures represent it, 



Q 



