Happon—The Actiniaria of Torres Straits. 439 
Tentacles—The ectoderm and entoderm are of about equal thickness, the 
mesogloea is very thin. The muscle layer of the ectoderm is not well developed, 
the endoderm is closely packed with zooxanthellae. 
sophagus.—The thick ectoderm of the cesophagus is thrown into half a dozen 
folds on each side; the gonidial grooves are well marked. 
Mesenteries—There are six pairs of perfect mesenteries, and six pairs of 
imperfect ones which bear retractor muscles for part of their length; there 
are also twelve pairs of incipient mesenteries, which consist solely of a strip of 
mesogloea that does not extend beyond the endoderm. Their arrangement is 
typical of the hexactinian plan. 
Transverse Section of a Mesentery of Hoplophoria cincta. Enlarged about 100 diam. 
The retractor muscles are moderately developed; the sparse plaits branch 
very slightly. Parietobasilar muscles are very weak, and have no mesogleal 
plaitings. 
The mesenteric filaments are simple ; they are very similar to, and apparently 
continous with, the ectoderm of the cesophagus. 
Gonads.—The specimen was immature, and no trace of generative organs could 
be detected. 
ASTERACTIS, Verrill. 
Phyllactidz (?) with a column which is versatile in form; the body-wall is 
firm and sub-coriaceous; simple, slender, pointed tentacles, tricyclic, forty-eight 
in number; capitulum with forty-eight radiating rows of small sessile, somewhat 
lobed and subdivided tubercles or papillz, increasing in size to the margin, which 
is crenulate or dentate with the last tubercles of each series; the length of these 
rows of papillee bears a relation to the corresponding tentacular cycle ; the twenty- 
four small ones extend only about a quarter of the distance from the margin of 
the column to the bases of the third cycle of tentacles. 
A, Bradleyi, Verrill, 1868, Trans. Connect. Acad. 1. 1868, p. 465. 
