No. I.] ACTINIARIA OF THE BAHAMAS. 65 
lotti’s name Gemmaria, since in its general characters the form 
to be described seems to resemble not a little their Gemmaria 
Ruzet, though differing decidedly from it in coloration. The 
forms included in the genus as here defined approach £fzzoan- 
thus, but differ in not incrusting shells, etc., and in having the 
mesenteries arranged on the microtypus. 
13. Gemmaria isolaia, n. sp: (PL 11.) Fig. 4; Pl TV., ‘Figs: 
19-20.) 
I met with this species on a single occasion only, while col- 
lecting at the eastern end of Rose Island. The individuals 
were scattered and buried up to the tentacles in sand. Owing 
to the depth of the water and the rapid tide I was unable to 
observe the coenenchyme, and it is quite possible that the ani- 
mals may be solitary, though I am inclined to believe that they 
are connected by a thin continuous lamellar coenenchyme. A 
single individual has a bud arising from its base. 
The column is cylindrical, broader above than below. In 
height it measures 2.5 cm., the disc when expanded measuring 
about 0.8 cm. in diameter. In color the column (PI. II., Fig. 4) 
is grayish yellow, owing to the incrusting matter. The disc and 
tentacles are ochre-yellow, the latter being spotted with white 
on their inner surfaces. The peristome and mouth are white. 
The ectoderm is protected by a not very strong cuticle, and 
is composed of several rows of cells, presenting an appearance 
similar to that figured by Erdmann for Zoanthus. It measures 
0.024-0.04 mm. in thickness. The mesogloea contains en- 
closures of foreign bodies —'sand, foraminifera and radiolarian 
shells, and sponge spicules —almost throughout its entire thick- 
ness, but towards the upper part these foreign substances are 
less abundant and are confined to a greater extent to the outer 
region of the mesogloea. This layer is about 0.4 mm. in thick- 
ness. The sphincter is single and imbedded in the mesoglcea, 
in its upper part being about half-way between ectoderm and 
endoderm, but lower down approaching the endoderm so as to 
be separated from it only by a thin layer. Above it consists of 
a single row of cavities, few in number, containing muscle cells, 
arranged in various directions, so that many are cut obliquely ; 
but below (Pl. IV., Fig. 19) it consists of a single row of circu- 
