A, FE. Verrill—The Bermuda Islands; Coral Reefs. 214 
feet in diameter are often remarkably symmetrical. When growing 
near together two masses often come in contact. by mutual growth 
and then they will often completely unite together by a grafting 
process, leaving only a thin line of epitheca to indicate the place of 
* T have one large and nearly symmetrical specimen consisting 
union. 
of three masses perfectly united together. When large numbers of 
the young start close together they may so unite that they form 
broad, irregular, crust-like growths, several feet across and only 2 to 
6 inches thick. When it starts near low-water mark it cannot grow 
Figure 71.—Meandra labyrinthiformis. Common Brain Coral. Young colony, 
somewhat reduced. Phot. A. H. V. 
upward to any great extent, as it is killed by a brief exposure to air 
and sunshine, and therefore it spreads out in flattened, cake-like 
forms, often dead in the center. 
* This property is not confined to this coral, but is common to all the species 
of Meandra, Favia, Mussa, Agaricia, Siderastrea, and doubtless to most other 
compound reef corals. I have personally observed it in numerous genera and 
species. Mr. Duerden has recently made some very interesting observations on 
the complete growing together, in the same way, of the recently attached and 
very young individuals of some of these corals, especially of Siderastrea. In 
such cases no evidence of such union can be detected in later stages. Amer. 
Naturalist, xxxvi, 1902; also Mem, Nat. Acad., viii, pp. 495, 528 ; and Carnegie 
Inst. Publ. No. 20, pp. 59, 60, 1904. 
