REPORT ON THE PENNATULIDA. 271 



found to have arranged itself in a single volute throughout, or into 

 two, three, or four between night and morning. The whole can relax 

 again into a straight line by their obliteration." * 



KoUikert suggests that the boring into the sand is effected by peri- 

 staltic waves of dilatation and contraction passing down the stalk and 

 rachis : the dilated parts acting as fulcra by completely filling up the 

 hole in which the stalk is planted, and so fixing it at one point, while 

 the wave of contraction, passing down below this fixed point, would 

 drive the end of the stalk deeper into the mud. The fixed point would 

 then relax, the terminal vesicle would dilate to act as a fulcrum, and 

 the longitudinal muscles would pull the whole colony down. It is, 

 however, not easy to see how a rapid retraction could be effected in 

 this manner. 



3. — Siippoited Nocturnal Habits. — According to Dalyell, Virniiliin'ii 

 when in captivity "remains contracted during the greater part of the 

 day, and the organs are seldom displayed before five or six in the 

 afternoon." On this point we would refer to the observations made 

 when considering the same statement concerning Pennatida. We have 

 there suggested that Pennatula ajipears to be "nocturnal" when 

 brought to the surface, simply because the amount of light it receives 

 in broad daylight is vastly in excess of what it receives normally at 

 the sea bottom, and that it is only towards evening that it is placed 

 under what to it are normal conditions as to amount of light. 



8. — Geofirapliical distribution. — 



r. mirabilis has been taken at a number of localities in different 

 parts of Europe. Like the Pennatulida generally it appears Lo be very 

 local, but to occur in large numbers where it is found at all. 



It has been recorded from several places on the coast of Norway 

 and Denmark ; from Belfast Lough, Gairloch, Oban, the island of 

 Inchkeith, near to Edinburgh, the Hebrides, and other Scotch 

 localities. 



In 1879 the Birmingham Natural History Society added a new 

 locality to the list by dredging a single specimen off Falmouth ; and we 

 may cite also, on Mr. Darbishire's authority, the stomachs of haddock 

 off Scarborough, as a place where Virgularia has been found. The 

 uncertainty whether these last specimens had been found by the 

 haddock near where they were caught, or had been brought from some 

 other locality, prevents our adding Scarborough definitely to the list 

 until the point has been determined. 



General Observations on FunicuUna, I'ennatula, and Vircpilaria. — 



All three genera are colonial forms, consisting of a number of 

 individual animals — the polypes — living organically connected together, 

 and to a greater or less extent dependent on one another. In all three 

 cases the colonies increase in size by the addition of new individuals 

 by the process of budding or gemmation, whilst new colonies are 



Dalyell : op. cit., p. 185. + KiUliker : op. cit., p. 205. 



