ALCYONELLA BENEDENI. 89 



Alcyonclla fungosa presents itself in the form of bro-wn fungoid masses of very variable 

 size and shape, attached to the surface of different fixed objects, as stones, pieces of wood, 

 fresh-water shells, &c. The masses frequently acquire a considerable size, weighing upwards 

 of a pound. They are often irregularly lobed, and when they grow upon the surface of a 

 cylindrical body, as a twig on the stem of some aquatic plant, usually surround it so as to 

 assume a somewhat spindle-shaped figure, gradually diminishing in thickness from the centre 

 towards the extremities. They are fond of attaching themselves to the branches of trees which 

 dip into the water, and then constantly exhibit lobed, pear-shaped masses pendant from the 

 extremities of the sprays. 



When a living specimen is examined in the water, its whole surface seems covered with 

 a whitish down, which a slight examination shows to be occasioned by the protrusion of 

 innumerable polypides. When removed from the water, the polypides shrink back into their 

 cells, and the surface then seems covered with a gelatinous investment, caused by the soft, 

 papilla-like, extremities of the tubes. These extremities contract no adhesion to one another, 

 like the rest of the tubes, and the ectocyst, as it passes over them, becomes very delicate and 

 transparent ; in dead specimens they shrivel up and disappear, and then the surface of the 

 mass presents a multitude of closely applied hexagonal or pentagonal orifices. The whole 

 production now assumes the appearance of a spongy, honeycomb-like mass, and this has not 

 unfrequently been mistaken for a fresh-water sponge. A vertical section shows it to be com- 

 posed of a vast number of tough, membrano-corneous-branched tubes, closely adherent to 

 one another, and each opening on the surface by one of the angular orifices, just mentioned. 

 Imperfect transverse septa may be seen at the origin of many of the branches. The tubes, 

 towards the end of summer, are loaded with mature statoblasts, which, on the rupture of the 

 coenoecium, escape in great numbers into the surrounding water. 



The colour of the living mass varies somewhat with the nature of the food and the state 

 of depletion at the time, the contents of the stomach being visible through the transparent 

 portion of the tubes. When the stomach is not filled with food, so as to impart an adventitious 

 colour to the mass, the latter is generally of a light-brown, or gray, upon the surface, and of a 

 darker brown in section. It is in perfection during the summer and autumn; in winter, 

 nothing is to be found of it but the empty and decaying coenoecium. 



A. fungosa is a widely distributed Polyzoon, having been found in Russia, France, 

 Prussia, Belgium, and the British Isles. It is curious enough that, though it is common in 

 England and Scotland, it has never yet been found in Ireland, where all the other British 

 genera are abundant. It prefers stagnant and slowly running waters. Some of the largest 

 specimens I have seen were in the Chelmar, a sluggish river in the county of Essex, which 

 has been widened and deepened into a canal, for the purposes of inland navigation. 



2. Alci/0}iella Benedeni, AWman. PI. IV, figs. 5 — II. 



Specific character. — Coenoecium fungoid; formed of numerous branched vertical tubes, 

 which are emarginate at the orifice, and furnished with a furrow. (Free) Statoblasts elongated. 



Synonym. — 1850. Alcyonella Benedeni, Allman, British Association Report. 



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