64 McMURRICH. (Vou. III. 
not containing any enclosures of ectoderm cells, and the endo- 
derm is much thicker than elsewhere, and is literally loaded 
with “yellow cells.” The disc resembles the tentacles in 
structure, but the ectoderm cells are less distinct, more nearly 
resembling those of the column, and the mesogloea contains 
enclosures of ectoderm cells. The stomodzeal ectoderm has no 
cuticle and is ciliated, and the mesoderm, containing enclosures 
of ectoderm cells, is thrown into slight longitudinal folds (PI. IV., 
Fig. 18). 
The mesenteries are arranged on the microtypus (Erdmann), 
and vary in number according to the size of the polyp, equalling 
in number the tentacles. The increase in number occurs by 
the formation of new pairs on either side of the ventral (macro-) 
directives, as has been described for other Zoanthidz by G. 
Miiller (84) and Erdmann. The mesogloea is thin, measuring 
only about 4; the basal canal is long and not at all wide, pro- 
ducing only a very slight basal thickening of the mesentery 
(Pl. IV., Fig. 17); and the musculature is weak, forming a single 
almost smooth layer covering the whole surface of the mesen- 
tery, the mesogloea not being raised into folds to support it as in 
the Zoanthus from the Bermudas described by Erdmann. In 
one mesentery I observed the basal canal communicating with 
one of the spaces in the mesogloea of the column wall. It seems 
open to question whether the cells of the larger cavities in the 
mesogloea are not in reality endodermal in their origin. 
In none of the specimens examined were any reproductive 
organs present. 
Genus GEMMARIA (Duch. and Mich.). 
Synon. — Gemmaria — Duchassaing and Michelotti, 1860. 
Epizoanthus (in part) — Verrill, 1868. 
Zoanthidz with sand or foreign matter imbedded in the meso- 
gloea; the coenenchyma is absent or lamellar; the mesenteries 
are arranged on the microtypus, and there is a single sphincter 
enclosed in the mesoglcea. 
An arrangement such as is described in the above definition 
is not included among those given by Erdmann (85), and I have 
consequently referred the single form which possesses it to a 
distinct genus to which I have applied Duchassaing and Miche- 
