126 MEMBRANIPORID^E. 



surface glistens when dried. The cells are arranged with 

 extreme regularity, and form a pretty and distinct lace- 

 work pattern on the frond. The structure is eminently 

 simple; spines, avicularia, and probably ooecia, are all 

 wanting. Grant describes the development of the ovum, 

 which is of a light-yellow colour, and its escape from the 

 cell itself into the water. 



Family VIII. Membraniporidae. 



CELLEPORID* (part.)i Johnston, Brit. Zooph. 



MEMBRAxiroRin.K (part.), Busk, B.M. Cat. 



FLUSTHELLABID.E (part.), D'Orbigny, Pal. Fran9. T. Crt. 



EsCHABiDjE (part.), id. ibid. 



K-< HAI:I:I.I.I.MI>.I: (part.), id. ibid. 



FLUSTKELLID^ (part.), id. ibid. 



FLUSTRINIDJS (part.), id. ibid. 



ELECTRINID^E (part.), id. ibid. 



MESJBRANIFORID.E, Smitt, Krit Forteckn. 



ZOARIUM calcareous or membrano-calcareous, incrusting 



(so far as British species are concerned) *. ZO<ECIA 



forming an irregular continuous expansion, or in linear 



series, with raised margins, and more or less mem- 



branaceous in front. 



THIS family represents an earlier stage of zooecial 

 development, as compared with the two following. The 

 calcification of the cell is always more or less imper- 

 fect ; and in a large proportion of cases the whole of the 

 front is merely closed in by a membrane, a condition 

 which we meet with in the immature cells of the old 

 Lepralian group. 



* There are fossil and other forms with an erect habit of growth, which 

 from the structure of their zocecia, should probably be included in this 

 family. 



