A, EF. Verrili— The Bermuda Islands; Coral Reefs. 231 
are generally truncate and double at the surface, with a naked 
groove or furrow interrupting the cost ; beneath the surface the 
wall, as seen in sections, is thick and nearly solid, with very few 
exothecal vesicles. | 
The principal septa in the younger specimens are rather thin and 
not very closely crowded, but in the largest one they become so 
thick distally that they appear crowded, the spaces between being 
less than their thickness; those of the last cycle are poorly devel- 
oped. The larger septa are rather wide distally and evenly rounded 
at the somewhat exsert summits, where they bear three or four 
angular, rather strong, but not very long, divergent teeth ; the teeth 
or denticles of the inner margin are usually 8 to 12 on the larger 
septa, of moderate length, wider at base, subacute, mostly increasing 
in size and length distally. In the younger specimens the teeth are 
sharply granulose or spinulose, but only moderately so in the adult. 
Columella moderately developed, lamellose and spinulose. The 
epitheca covers the larger specimen almost to the margin, but one 
of the younger ones, which has very little of it, has wide and thin 
lamellar coste, finely serrulate below, but thickened and covered 
with strong triangular teeth distally, toward the margin. 
This species resembles rigida in the solidity of the walls, but that 
species has smaller, mostly astreiform calicles, and different septal 
teeth. It is nearest related to M. annectens, but the latter is a much 
larger, coarser, and heavier coral, with larger calicles, stouter and 
more exsert septa, and much larger and longer distal and terminal 
teeth, so that it appears much more spinose. 
This species appears to be rare at Bermuda and unknown else- 
where. I have not seen more than half a dozen specimens among 
the hundreds of specimens of Mussa examined. 
Additional notes on the species of Mussa recorded by Quelch. 
Many species of Mussa (as Isophyllia) were recorded from Ber- 
muda by Quelch.* Most of those that he enumerated are slight 
variations of MW. fragilis and M. dipsacea (see above, pp. 223-225). 
In addition to those already discussed, he recorded marginata Duch. 
and Mich., australis Edw. and Haime, multilamella (D. and Mich., 
1866, as Lithophyllia), and I. spinosa Edw. and Haime. 
* Of the 28 species of true corals recorded by Quelch, 13 are here regarded as 
synonyms. He enumerated 11 species of Isophyllia and Lithophyllia, all of 
which are here referred to the two common species of Mussa (fragilis and 
dipsacea) with one possible exception (his marginata). 
