Full Download Ebook PDF Skills For Accounting Research 3E by Collins Salzman Ebook PDF Docx Kindle Full Chapter
Full Download Ebook PDF Skills For Accounting Research 3E by Collins Salzman Ebook PDF Docx Kindle Full Chapter
Full Download Ebook PDF Skills For Accounting Research 3E by Collins Salzman Ebook PDF Docx Kindle Full Chapter
Fig. 161.—Cavernularia obesa. Au, autozooid; Si, siphonozooid; St, stalk. (After
Kölliker.)
CHAPTER XIV
The gonads in the Zoantharia are borne upon the sides of the
mesenteries and are usually in the form of long lobed ridges instead
of being spherical in form, and situated at the edges of the
mesenteries as they are in the Alcyonaria.
Nearly all the zooids and even the colonies of the Zoantharia are
unisexual, but some species, such as Manicina areolata (Wilson),
Meandrina labyrinthica (Duerden), Cerianthus membranaceus, and
others, are hermaphrodite. Mr. J. S. Gardiner has recently given
reasons for believing that the genus Flabellum is protandrous.
There are a great many cases among the Actiniaria in which the
embryos are retained within the coelenteron, or in special brood
pouches of the parent (p. 379), until a stage is reached with twelve
or more tentacles.
The oval or pear-shaped larva swims about for a few days or hours,
and then settles down on its aboral end. In swimming, the aboral end
is always turned forwards. In the larva of Lebrunia coralligens and
Rhodactis sancti-thomae, a distinct sense organ has been observed
upon the aboral extremity, and a similar but less distinct organ on the
larva of Actinia equina. These organs are of considerable interest, as
they are probably the only specialised sense organs known to occur
in the Zoantharia.
Similar wonderful variety and beauty of colour are seen in the Sea-
anemones of other parts of the world. Thus Saville Kent[403] in
describing a species of the gigantic Stoichactis of the Australian
Barrier Reef says, "the spheroidal bead-like tentacles occur in
irregularly mixed patches of grey, white, lilac, and emerald green, the
disc being shaded with tints of grey, while the oral orifice is bordered
with bright yellow."
Sub-Order 1. Actiniina.
Fam. 1. Halcampidae.—This family is clearly most closely related to
the Edwardsiidea. There are, however, twelve complete mesenteries
of the first cycle, and a second cycle of more or less incomplete
mesenteries. The tentacles are usually twelve in number, but may be
twenty or twenty-four. There is no pedal disc, but the base is swollen
and rounded or pointed at the end.