Corallines, fyc. 2465 



green twinkling spark, which proved to be one of the worms alluded to. The light 

 proceeding from the polype-cells was very feeble, and easily extinguished by fresh 

 water ; but the shining quality of the slender Annelides retained its vividness after 

 twelve hours' immersion, and finally ceased in two days. The species most abundant, 

 in the immense bunches already mentioned, were Plumularia falcata, Sertularia abie- 

 tina, and Thuiaria Thuja : the last-mentioned is daily gathered, in every stage of 

 growth, on a variety of objects : it is commonly found adhering to old valves of Cy- 

 prina Islandica and decayed shells of Buccinum undatum ; but the largest and best 

 specimens are torn by the fishermens' hooks from the surface of large stones lying at 

 a depth of thirty or forty fathoms. Those met with on worn shells and small frag- 

 ments of stone appear to have their growth retarded by the rolling motion of their 

 support, and are seldom higher than six or eight inches ; but many specimens mea- 

 suring sixteen inches have been given to me, which were plucked from a firmer bed. 

 The greater part of the collection which I made was brought from deep water; but 

 occasionally splendid specimens of the « lobster horn ' were taken up on the crab-c'ages, 

 from the rocky ground close on shore. 



The most plentiful zoophyte which burdens the lines of the fishermen is Alcyo- 

 nium digitatum. This white species, known by the name of ' dead men's hands,' is 

 seen on almost every hook. The red-coloured A. glomeratum, which is not so com- 

 mon, forms a pretty contrast with it when the polypes are fully expanded. I have 

 kept both alive for a period of two months : the latter was first dead ; the former only 

 survived a few days. In the bed of the sea A. digitatum grows upon anything which 

 lies there— pieces of wood and stone, old shells and thick sea-weed : it is much in- 

 fested by a species of burrowing shell, which bores through its substance, without, 

 however, leaving a trace of its entrance. I have taken six or eight of these shells 

 from a small portion of Alcyonium ; and so firmly were they imbedded by the con- 

 traction of the polypes, that the destruction of the specimen was necessary for their 

 release. The shapes which this zoophyte assumes are manifold and curious. To the 

 five-fingered lumps often procured, the title ' dead men's hands' is truly appropriate ; 

 and on some objects it appears like an incrusting fleshy sponge. In this state it forms' 

 the outer covering of the India-rubber-like tubes of certain Annelides, and is also found 

 spreading over the branches of trees, and other pieces of wood which have become 

 waterlogged and sunk to the bottom ; but should these be pre-occupied with other 

 corallines, it will dispute the surface, and, as is generally the case, envelope the objects 

 by its more rapid growth. 



Most of our pelagic animals possess a luminous property in some degree; and 

 perhaps not the least interesting of the class are those brittle Annelides which exhibit 

 so often a voluntary emission of light. Irritation is the main cause of the brilliant 

 fires displayed by the plant-like zoophytes, and other species, of which the minute 

 Acalephae are common instances. About midnight, I have often looked with interest 

 on the exhibitions of these Medusae, on being alarmed by a handful of small stones 

 thrown into the water: seated in a small boat in the harbour, I showered the gravel 

 around me till the sea appeared like a sheet of glass studded with sparkling diamonds, 

 —a sight well worth taking the trouble to enjoy. At the same hour of night I have 

 extended my rambles to the rocky shore, where the receding tide had left pools enough 

 for ample observation, and there seen the brittle worm shooting like a meteor along 

 the sandy bottom, and wriggling its way into the corners and crevices of the rocks, 



