42 CORALS 



The latter are clearly for the purpose of attachment to 

 some foreign object, and the former may act as additional 

 supports for the specimens that are imbedded in sand and 

 mud. Specimens taken from the same locality are extremely 

 \'ariable as regards both wings and roots, and it seems 

 probable that these structures are formed in response to the 

 conditions of the immediate environment and cannot be 

 regarded as of any generic or specific importance. A few 

 specimens have been found which were attached to a rock 

 or shell by the side of the epitheca, and such specimens 

 usually exhibit additional abnormalities of form. 



Family 2. Oculinidae 



The corals of this family form large imperforate branch- 

 ing colonies bearing numerous calices, separated from each 

 other by considerable intervals of coenosteum. 



As in all the colonial corals, there is immense variety in 

 the size, manner of branching, occurrence of anastomoses, 

 and the distribution of the calices. In recent Oculinidae, 

 however, although the main stem may be nearly an inch 

 in diameter, the branches are usually slender, | to | inch 

 in diameter, and terminate in blunt extremities. Massive 

 and encrusting forms of colonies are rare. 



The genera Amphihelia and Lophohelia belonging to 

 this family are of special interest, because they are the only 

 large colonial corals that are found in British seas. They 

 are widely distributed in deep water in the North and 

 South Atlantic, in the Mediterranean Sea, in the East and 

 \\'est Indies, and elsewhere. They come within the British 

 fauna off the west coast of Ireland and off the coast of 

 Cornwall. 



A general account of the structure of Lophohelia has 

 been given on p. 28. 



Amphihelia. — The genus Amphihelia resembles Lopho- 

 helia very closely in its mode of growth and ramifications, 

 but is said to differ from it in having a shallower depth of 

 calyx, in a greater regularity of the septa, and in the presence 

 of a true columella. In Lophohelia, moreover, there may 



