~ 
the Actiniartan Family Alicide. 5 
vesicles, being smaller and showing a long spiral thread 
coiled up inside. They are mostly limited to the upper 
naked part of the column. The mesogloea is thrown into 
deep plaitings to support a strong endodermal muscle. 
The vesicles have a broad ectoderm, which, in limited 
places, evidently corresponding with the thickenings at the 
tips, is crowded with enormous nematocysts rounded at each 
end. ‘These are clear or contain granular matter, and have 
only a very short spiral thread; nearer the origin of the 
vesicles—that is, on the peduncle—they are smaller and have 
a long spiral thread as in the column-wall. Numerous 
strongly staining elongated bodies occur in the deeper part of 
the ectoderm, evidently developing nematocysts*. The 
mesoglea is thin, and the endoderm, now decomposed, contains 
much granular pigment matter. 
Sphincter muscle——The sphincter muscle is of the same 
character as that found in Alicia coste, i. e. endodermal, 
diffuse, and elongated. The plaitings of the mesoglcea are, 
however, better developed than in that species, becoming 
more dendriform and thinning out for some distance. The 
material does not admit of a determination of the exact limits 
of the muscle, but it appears to commence just below the 
tentacles and to extend into the region of the vesicles, being 
merely a concentration of the circular endodermal muscle 
occurring throughout the column-wall. 
Tentacles.—The ectoderm of the tentacles is thick and 
richly supplied with nematocysts like those of the column- 
wall and arranged at right angles to and close to the surface. 
An occasional larger one, similar to the vesicular form, may 
be met with. The mesogloea is broad, and forms small 
dendriform outgrowths on its internal border for the support 
of the strong circular endodermal muscle. 
(sophagus.—The ectoderm of the cesophagus is a deep 
layer and much folded. It contains numerous elongated 
stinging-cells and many large cells with pigmented granular 
contents, arranged in a nearly central zone, 
The mesogloea is narrow and supports a weak ectodermal 
and endodermal musculature. 
Mesenteries.—'l'wenty-four pairs of mesenteries are present, 
similar in arrangement to those of A. costw, viz.: six perfect 
pairs, two pairs being directives; six pairs forming a second 
cycle, alternating with the first; and twelve pairs in a third 
* In the description of A. coste it is stated (‘ Annals,’ 1895, xv. p. 216), 
that the vesicles are not batteries of nematocysts. A re-examination of 
the sections in the light of other forms shows that they must be so regarded, 
the so-called gland-cells being developing stinging-cells. 
