ORDER ACTINOIDEA. 43 
tentacles are tubular, and expansion takes place, as in the species 
before described, by means of water, received from without, and 
injected into these organs and other parts of the animal. The 
Tubipore secretes a calcareous tube, or corallum, which is stiff and 
firm below ; but near the extremity it is still flexible, and the animal 
contracts by drawing its head and tentacles into the tube, like turn- 
ing in the end of the finger of a glove. Figure 1 represents one of 
the contracted animals, with the tube laid open by a longitudinal sec- 
tion, showing the interior structure. The pear-shaped part above con- 
tains the withdrawn and contracted tentacles; and the dark spots, near 
the bottom of the same, are the openings into four of the tentacles, by 
which water enters from the visceral cavity, when the animal expands 
itself. 
37. The visceral cavity is long, tubular, and contains eight fleshy 
lamelle. These lamelle aid, by their muscles, both in the contraction 
and expansion of the polyp, in a manner which will be understood 
without explanation, by a glance at figure 1b. The stomach is cylin- 
drical and very short compared with the whole length of the visceral 
cavity; and, as in the preceding species described, it is connected with 
the sides of the cavity by the visceral lamelle. 
Six of these lamelle were spermatic, being bordered below by the 
white convoluted cord, while the other two gave origin to large 
clusters of milk-white ovules, which occupied nearly the whole dia- 
meter of the cavity. ‘These ovules were of various sizes, and sphe- 
rical in shape, or nearly so. Figure 16 shows their position in the 
tube, and 1c the appearance in profile of one of the lamelle with the 
attached ovules. 
Some observers have found all the lamelle bordered with the white 
filament, and others describe them as all bearing clusters of ovules. 
In these instances, it would seem that the sexes were distinct, in one 
case the animal being male, and in the other female. The subject 
requires farther investigation. 
In the characters of the Tubipore we have the characters of the 
Alcyonaria generally, a large tribe of zoophytes. The eight fringed 
tentacles, and the eight visceral lamelle attaching the stomach to the 
sides of the cavity, and extending below to the bottom of a tubular 
visceral cavity, distinguish them at once from other Actinoid polyps. 
The ovules in some species have been seen to escape by the mouth, 
and this therefore appears to be the general mode in all the Acti- 
