Macuire—WNotes on Certain Actiniaria. 723 
The surface of the column is smooth. The ectoderm is trans- 
parent, showing the insertion of the mesenteries, and the gullet 
which reaches about half way down the column. 
The tentacles are arranged on a circular dise in about four 
cycles; they are very numerous, nearly 200 in one specimen, 
small conical, all similar. The mouth is an elongated slit; there 
are two gonadial grooves. ‘The pedal disc is well marked in most 
of the specimens. 
One,specimen was stained in carmine, imbedded in paraffin, 
and cut transversely. Sections through the gullet show two pairs 
of directives with four pairs of complete lateral mesenteries, making 
altogether six primary mesenteries, all of which are sterile. 
There are six pairs of secondary mesenteries bearing ovaries 
and mesenterial filaments. Twelve pairs of tertiary sterile mesen- 
teries. Twenty pairs of sterile mesenteries of the fourth cycie; 
these are very small, and not raised above the endoderm (fig. 5). 
Sections below the gullet show the same arrangement; the 
primaries bear mesenterial filaments, but no gonads. The number 
of mesenteries is the same. The shape of the mesenteries was a 
good deal affected by pressure, the specimen being distended by 
ova; but there is no doubt that some pairs both of primary and 
secondary mesenteries are of unequal length. 
A second specimen was also cut transversely, showing the same 
number and arrangement of the mesenteries as the former; but in 
this specimen the primaries, including the directives, were fertile ; and 
some pairs of the secondary mesenteries (but not all) seemed 
to be also fertile: mesenteries of the third and fourth cycles as in 
the former specimen. 
Sphincter.—The sphincter (fig. 4) is present in the upper part of 
the column only; it is mesogleal, occupying the whole thickness of 
the mesogloea, and ceasing abruptly at the oral disc. It does not 
taper much at its lower extremity, but is of the same width 
throughout. 
Ectoderm.—There is no cuticle. The ectoderm of the column 
and disc is of the usual type. ‘There is no ectodermal muscle on 
the column. The ectodermal muscles of the tentacles are well 
developed; that. of the dise is fairly developed. There are nume- 
rous thin-walled stinging cells in the ectoderm of the tentacles; 
thick-walled stinging cells are not so common; in other parts of 
