178 J. E. Duerpen—Jamaican Actiniaria : 
feeble circular endodermal muscle is, however, present in the perioral region of 
the dise. 
The tentacles in this species therefore differ from those of the two previous 
forms in not having a capitulum histologically distinct from a stem, and also in 
not being much differentiated in structure from the disc itself. 
Towards the middle of the disc, that is, in the naked area, the details, however, 
approach more closely those of the column; gland cells, with highly refractive 
contents, occur in the ectoderm, and the endodermal muscle is stronger. 
The wall of the stomodzeum is much folded, both vertically and transversely. 
The ectoderm is broad, ciliated throughout, and bears numerous, long, granular, 
gland cells, and a less number of oval-shaped nematocysts, much larger than those 
of the tentacles. -A very weak ectodermal musculature is discernible. The 
endoderm is slightly pigmented like that of the dise and tentacles, and contains a 
few highly refractive gland cells. 
A wwansverse section through the polyp, in the middle stomodeeal region, shows 
to the naked eye the following details :— 
Twenty-five pairs of mesenteries, all of which are complete; of these two 
pairs are directives, so that of the other pairs, twelve occur on one side, and 
eleven on the other. No incomplete mesenteries are developed. A single deep 
gonidial groove, with very smooth walls and much thickened mesoglcea, 1s included 
between one of the pairs of directives, but no indication of a second is presented 
in connexion with the opposite pair. 
The inner mesenterial stomata occur just within the lips, and the outer a little 
from the column-wall, about a centimetre below the sphincter muscle. Both 
are rather large apertures of about equal size. The retractor muscles of the 
mesenteries are large, thick, oval, or reniform projections from one face, and are 
attached by only a narrow, short pedicle; on the opposite face of the mesentery 
a very distinct pennon arises a little beyond the insertion of the mesentery in the 
column-wall. 
In a section below the stomodeal region, the same twenty-five pairs of 
mesenteries occur, and, with their mesenterial filament and gonads, completely 
fill the coelenteron. Towards the basal part of the column, alternate larger 
and smaller pairs are exhibited, but irregularities occur, In one region 
seven pairs being of the same size. The number of mesenteries bearing 
mesenterial filaments begins to diminish, until a little above the base they are met 
with only on four. In the single example studied, the gonads were bright red in 
colour, and a reddish oil was extracted by alcohol. 
The microscopic appearance of a portion of a mesentery, near its place of origin 
in the column-wall, is represented in Pl. xur., fig. 2. The pennon is seen to be 
strongly developed, and the mesogloea long and deeply plaited on both sides. In the 
