230 A. EF. Verrill—The Bermuda Islands; Coral Reefs. 
known to me since 1864. It was a young specimen of this species 
that I recorded from Bermuda in 1864 (as Lsophyllia rigida, coll. 
Mus. Comp. Zool.), but the subsequent discovery of Dana’s type of 
rigida in the collection of Yale University proved long ago that it 
is a distinct species. (See these Trans., xi, p. 127, pl. xxv, figs. 2, 3, 
for the true MW. rigida, which has not been found in Bermuda. )* 
A careful examination of the photographs of all the types of the 
forms described by Duch. and Mich. shows that it cannot be referred 
to any of them. It appears, therefore, to still lack a name and a 
place in the system. It resembles multiflora only in the small size 
and rapid division of the calicles. 
83 
Figure 83.—Mussa rosula, sp. nov. Young; natural size. 
Figure 84.—M. multiflora (?), a young specimen, about natural size. Both phot. 
Dy, Aw aen Ve 
This species, when mature, forms convex masses up to 4 to 5 
inches in diameter. The calicles are unusually small for the genus, 
and many soon become isolated and nearly circular, especially the 
marginal ones ; most of the calicles are only 10 to 12™™ in diameter 
before division, but some of the marginal ones may be 18 to 20™™, 
in the largest specimen. They are usually rather deep with steep 
sides. The intervening collines may be simple and solid in the 
young (as in the example figured), but in the larger specimens they 
* Judging by a photograph of the type, sent to me by Dr. Vaughan, (see p. 223,) 
the Acanthastrea dipsacea Duch. and Mich., op. cit., p. 78, 1860, is identical 
with the true M. rigida of Dana. 
