ALCYONELLA FLABELLUM. 91 



Iconography. — The original figures of Van Beneden. 



Habitat. — Stagnant and slowly running waters, adhering to the submerged steins of 

 aquatic plants. 



Localities — British: Chelmar Canal, Essex. G. J. A. — Reading. Mr. Bowerhank. 

 Foreign : Belgium. Van Beneden. 



This species was first characterised by M. Van Beneden, who discovered it in Belgium, 

 and described it in the 'Memoirs of the Royal Academy of Belgium,' for the year 1848. In 

 September, 1849, I received from Mr. Bowerbank a living specimen, obtained in the neigh- 

 bourhood of Reading ; it was attached to a decayed twig, along with A. fungosa, and had 

 developed itself in the form of two flabelliforra masses, attached to one another by a short 

 simple tube, as figured by Van Beneden. In July of the following year, I met with the same 

 species in the River Chelmar, attached to the petioles and under surface of the leaves of 

 Nymphaa alba. 



A. fiabellum is a small, but very pretty Polyzoon, and rendered very striking by its mode 

 of growth in two flabelliform fasciculi of tubes, each fasciculus closely adherent by one face 

 to the surface of the body on which it is developed. The largest specimens I have met with 

 measure about half an inch in their longest direction. The ectocyst is dark brown, becoming 

 abruptly lighter towards the orifices ; the furrow, commencing wide in the vicinity of the 

 orifices, extends as a narrow transparent line along the free surface of the tubes, giving them 

 the appearance of being slit along one side. 



The polypides have about forty tentacula, and the margin of the calyciform membrane is 

 distinctly festooned. 



I have not observed the statoblasts, as these bodies were not present in any of the spe- 

 cimens I examined ; they are, however, figured and described by Van Beneden as broadly 

 elliptical. 



