Poly zoa from Barents Sea. 283 



means of attachment. The fibres originate in certain cells 

 whose surface is completely invested by a membranous enve- 

 lope, and are a direct extension of this epidermal covering. 

 They pass downwards along the surface, and as they advance 

 become closely appressed one to the other, so as to constitute 

 at last a cable-like stem, composed of many strands. The 

 extremities bifurcate and run out into long slender fibres, 

 which form a considerable mass at the base. A similar 

 peculiarity is exhibited by Eschara flabellaris, Busk*, and 

 Flustra marginata, Kraussf ; but in these cases the fibres, 

 though traversing the zoarium in various directions (at least 

 in the latter of the two species), are principally aggregated 

 along the margin, where they form a thickened rib. Both 

 these forms are South-African. 



Gray has instituted a genus (Flustramorpha) for these 

 forms, and has taken F. marginata as the type. It is really 

 based on a single character (the presence of the tubular fibres), 

 which is the only distinctive element in his diagnosis. His 

 account of the orifice of the zooecium is quite unintelligible ; 

 and the other points noted are all common to Flustramorpha 

 and a large section of the old Escharine group. 



The presence of the tubular fibres, however, cannot, in my 

 judgment, be accounted a generic distinction : these structures 

 are essentially identical with the (so-called) radical fibres, which 

 occur on so many of the Polyzoa, and to which no special 

 significance attaches. This view is confirmed by an exami- 

 nation of the zooecia of such a form as Eschara flabellaris. 

 Though the mode of growth is Escharine, the cells are those 

 of a Microporellaj mihi, and, I believe, are specifically iden- 

 tical with those of the common M. ciliata, Pallas. I have 

 already described a variety of the latter, which assumes an 

 erect foliaceous habit, and has the cells in two layers, placed 

 back to back} ; and it is a question whether Eschara flabellaris 

 should be accounted any thing more than another variety or 

 form of this protean species. 



In Flustra solida, Stimpson, we have a totally different 

 type of cell (PI. XV. fig. 3) ; and it would be quite impossible 

 in any natural system to rank it with Eschara flabellaris on 

 the strength of the supporting fibres, which are common to 

 them both. 



Gray's genus, then, is quite untenable ; and the species com- 

 posing it must be ranked according to the character of their 



* British-Museum Cat. part 2, p. 91, pi. cvii. figs. 7-10. 

 t Corall. undZooph. der Sudsee,p. .'^5, pi. 1. fig. 3, a-d. 

 X Ilistoiy of the Brit. Mariue Polyzoa, vol. i. p. 210. 



