212 A, E. Verrill—The Bermuda Islands; Coral Reefs. 
It varies greatly in the form and breadth of the ridges between 
the grooves. Young specimens, 2 to 4 inches thick, often have very 
wide and double ridges (var. Stokesii, tig. 71a); later on, the wide 
WASTE 
Lt? FANT Y ny NY * 
> , tft} i ad 
Figure 7la.—M. labyrinthiformis var. Stokesii, slightly enlarged: a, b, c, d, places 
where buds were about to develop. 
Figure 71b.—M. labyrinthiformis, partially expanded polyps, enlarged ; phot. 
from colored drawing. 
ridges divide and new grooves grow in between them. The wide 
ridges may also appear in larger specimens, either over the whole 
coral or in some particular places.* 
Figure 71¢.—M. labyrinthiformis, a calicle at the end of a series, with a 
nearly contracted polyp, and a diagrammatic sectional view of the coral, to 
show the relation of parts. Drawn by the author from the living coral. 
In full expansion the disks of the polyps rise up to or somewhat 
above the level of the summits of the collines, so that the bounding 
furrows may be seen above their walls while the disks become much 
wider than in their partly contracted condition, so as to occupy 
* For a fuller account and illustrations of these variations, see these Trans., 
vol. xi, pp. 70-78, pl. x, figs. 1-8; and Zoology of Bermuda, article 11, same 
plate. 
