A. E. Verrill — Bermudian and West Indian Reef Corals. 119 



Plate XVIII. Figure 2. Plate XIX. Figures 2, 3. Plate XX. Figure 2. 



This species occurs in abundance at the Bermudas, in shallow 

 water (1 to 20 feet) on nearly all the reefs, and also along the shores 

 attached to rocks, and even to small stones on shell-sand bottoms, 

 where other corals do not grow. It is very abundant even in 

 Harrington Sound, whei*e but few species of corals are found, owing 

 to the less density of the water. 



I have personally collected and studied hundreds of specimens of 

 this and the following species, and have kept large numbers alive, to 

 ascertain, if possible, whether two or more species occur there, and 

 to learn the character and extent of the variations. 



Probably no coral varies more than this in form, mode of growth, 

 union and separation of the calicles, and consequently in the size 

 and form of the calicles, character of the columella, number and size 

 of the teeth of the septa, extent of the epitheca, etc. 



Therefore many nominal species have been founded, especially by 

 Duch. and Mich., on mere stages of growth and on ordinary indi- 

 vidual variations in the mode of growth, union of the walls, etc. 



The colors of the living animals of this and fragilis are also 

 extremely variable, and often very beautiful. Most commonly they 

 are variegated with gray, lavender-blue, green, and flake-white in 

 variable proportions. But specimens often occurred, especially in 

 1898, rarely in 1901, that were largely or wholly bright emerald- 

 green, or grass-green. I have had some that were bright green over 

 one-half the surface, and lavender and gray on the other half. The 

 difference in the external appearance of the animals of this and 

 fragilis are slight. Therefore the color of the animal cannot he 

 used to distinguish species nor even varieties. 



The same is true of the isolation and union of the calicles in series, 

 for a single specimen often shows the extreme conditions on its 

 different parts. The collines generally have simple, solid, rather 

 thick walls, but sometimes they are double with a groove on the 

 summit, as is the case more commonly in fragilis. 



This species has a heavier and more solid coral than fragilis, with 

 stronger and thicker walls. It can best be distinguished by the 

 decidedly thicker and closer septa, which have stronger, stouter, and 

 more regular, spiniform teeth on their edges, the size of the teeth 

 decidedly increasing toward the columella, where the septa arc also 

 usually distinctly thicker. 



The calicles, when well grown, are generally broader, more flar- 

 ing, and more shallow. The costse are less prominent, thicker, 



