BRITISH ZOOPHYTES. 241 



Mr. Hincks has studied the purpose of this organ, and, 

 in his opinion, considers that " at certain seasons it is 

 the channel through which cercarice are ejected from 

 the perigastric cavity. The connection proved to exist 

 between this organ and the cercarice — rwhich must be 

 regarded as spermatozoic bodies — may be accepted as 

 conclusive evidence that it is subservient in some way 

 to the function of generation." 



5. M. MEMBRANACEA, Limi. Plate XIX. fig. 5. 

 Flustra membranacea {Linn., MiilL, E. and 8., Flem., 



Lamx., B. Q. G., D. L., G. J.), F. telacea [Lamh.), 

 Reptoflustra telacea {B'Orh). 



Hab. : Common. 



This zoophyte is commonly found spreading in gauze- 

 like areas over the fronds of fiici. It spreads to a 

 remarkable extent. Dr. Landsborough and Dr. John- 

 ston have both seen specimens as much as 5 feet in 

 length, with a breadth of 8 inches; and the former 

 observer calculated that " this web of silvery lace had 

 been the work and the habitation of above two millions 

 of industrious and, we doubt not, happy inmates." The 

 cells are quadrangular and oblong, with a blunt spine 

 at each upper angle. 



On some of the cells of this species occasionally 

 occur long tower-like transparent processes or cells, 

 which have been considered by some as ovicells, and 

 by others as abnormal growths. 



This is the " Chagrin (Shagreen) Sea Mat " of Ellis 

 (Ellis and Solander, N. H. Z., 18). 



6. M. HEXAGONA, Bush. 



Flustra coriacea {G. J., D. L.) . 



Hab.: Isle of Man (Forbes), Peterhead (Peach), 

 Coast of Devon {Miss Cutler). Rare. 



R 



