288 Z. ASCIDIOIDA. Flustra. 



Flustra membranacea, Lin. Syst. 1301. Fabric Faun. Groeiil. 437, no. 



446. Mull. Zool. Dan. prod, 253. Ellis and Soland, Zooph. 18. 



Turt. Gmel. iv- 665. Wern. Mem. i. 563. Turt. Brit. Faun. 21 C 



Stew. Elem. ii. 437. Bosc, Vers, iii. 144. Corall. 47. Hogg's Stock. 



36. Flem. Brit. Anlm. 536. Johnston in Trans. Newc. See. ii. 265. 



La F. membraneuse, Blainv- Actinol. 450 Fl. telacea. Lam. Anira. 



s vert. 2de edit, ii- 223. Grant in loo. s. cit. iii. Ill La naem- 



branipore membraneuse, B!ainv. Actinol. 447. 

 Hab. On the frond of Laminaria digitata. common. 

 Polypidom forming- a gauze-like incrustation on the frond of the 

 sea-weed, spreading irregularly to the extent of several square inches, 

 in general, thin, and closely adherent, but sometimes becoming thick- 

 ish, and then capable of being detached in considerable portions ; cells 

 very obvious to the naked eye, oblong, quadrangular with a blunt hol- 

 low spine at each angle. In many specimens there are some anoma- 

 lous processes, a quarter of an inch in height, scattered over the sur- 

 face : they arise from within the cells, are simple, horny and tubular, 

 but closed at top. Ellis conjectured they were ovaries, but the con- 

 jecture is certainly unfounded. — When the polypes are all protruded 

 they form a beautiful object under the microscope, from their num- 

 bers, their delicacy, the regularity of their disposition, and the viva- 

 city of their motions, now expanding their tentacula into a beautiful 

 campanulate figure, now contracting the circle, and ever and anon 

 retreating within the shelter of their cells. The tentacula are nume- 

 rous, filiform, white and in a single series. 



9. F. LINEATA, cells oval, separate, the margin armed with 

 several short equal spirious denticles. Professor Jameson. 



Plate xxxvii. Fig. 4. 

 Flustra lineata, Zzn. Syst- 1301. Mull. Zool. Dan. prod. 253. Fabric. 

 Faun. Groenl. 437. Turt. Gmel. iv- 665. Corall. 46. Jameson in 



Wern. Mem. i. 563 La F. lineee, Blainv. Actinol. 450 F. spi- 



nifera, Johnston in Trans. Newc. Soc. ii. 266, pi. 9, fig. 6 F. hir- 



ta? Bosc, Vers, iii. 144. Risso, L'Europ. Merid. v. 334. Corall. 49. 

 Hob. On stones at low-water mark in Berwick Bay, G. J. Ork- 

 ney Islands, Jameson. 



Polypidom membranous, of a horny texture, yellowish-brown, 

 rough, closely adnate, thin, spreading irregularly : cells scarcely visi- 

 ble to the eye, separate by a space not equal to the cell in breadth, 

 the marginal teeth stout and somewhat inclined inwards. 



10. F. ? carnosa, ^^ sid)stancejleshy ; cells remote, aperture 

 contracted, armed at the top with spinous processes." Jameson. 



Plate xxxvii. Fig. 5. 

 3 



