328 HISTORY OF BRITISH ZOOPHYTES. 



spreading irregularly, formed of a single layer of alternating 

 approximated cells ; cells oval, horizontal, membranous, the 

 aperture patulous, with a hard calcareous rim. — Johnston. 



1. Membranipora pilosa, Ellis. 



Hab. On seaweeds, abundant, and also on shells. 



This zoophyte is often met with in greater abundance 

 than many would wish, as it completely covers, and in a 

 manner conceals, the objects on which it grows. Yet, though 

 when it is of a dirty white colour, smothering some delicate 

 alga, we might wish that it were away, when the attention 

 is turned to it in some of its finer aspects it is truly beau- 

 tiful. TMien it is of a fine fawn-colour, clothing a little 

 branching seaweed, it is quite lovely ; and not less so when 

 it spreads itself freely on some broad-leaved seaweed, as it 

 oft€n does, either irregularly or in a stellated form. It has 

 then a silvery appearance, and many, when for the first 

 time they examine it with a lens, and see its sharply-toothed 

 and granulated cells, are so struck with its beauty that they 

 conclude that this exquisite production must be very rare. 

 Beliind the mouth of each cell there is a very long tubular 

 bristle. 



The polypes of this species are furnished with a singular 

 organ, described by Dr. Farre and by the Rev. T. Hincks. 



