422 Rey. T. Hincks on a new Genus of Hydroida. 
These organs are capable of great elongation and contraction, 
and execute the most vigorous movements, stretching themselves 
out with apparent eagerness, and twisting in all directions. My 
attention was first drawn to the zoophyte by a number of them, 
disposed on the creeping stolon, which were in a state of most 
lively excitement, and manifesting a large amount of muscular 
energy. 
One of these organs is almost always attached to the hydro- 
caulus a little below the calycle, and when in a state of exten- 
sion it rises above it; and as it twists itself about, with its for- 
midable armature ready for instant action, it has all the appear- 
ance of a purveyor to the polypite. Many of them are also 
distributed upon the hydrorhiza. 
A striking feature of the genus Ophiodes is the constriction 
of the body of the polypite, dividing it into two well-marked 
regions—the oral, including the mouth and the tentacular 
circle and a kind of quasi pharynx, and the aboral, traversed by 
the digestive cavity. 
The polypite does not extend to the bottom of the hydrotheca, 
but rests on a membranous diaphragm that shuts off the upper 
third of it and forms a cup-shaped chamber. This diaphragm 
is perforated in the centre, and through the orifice the body is 
linked on to the ccenosarc, that traverses the lower portion of 
the calycle. 
O. mirabilis, nu. sp. 
Hydrocaulus erect, slightly branched, rudely annulated at the 
base, and jointed at intervals throughout. Hydrothece in the 
form of a vase, bulging slightly immediately above the base ; 
the sides incurved, expanding gradually towards the top, with 
an everted rim ; a single ¢entaculoid organ on the stem a little 
below the calycle, and many distributed on the stolon ; polypites 
tall, the inferior portion of the body clavate, the oral funnel- 
shaped; tentacles about fifteen, a brownish cluster of thread- 
cells between each pair on the connecting web. Reproductive. 
organs unknown. 
Height about 71, of an inch. 
The branching of the Ophiodes mirabilis, as I have seen it, is 
of the simplest kind, usually consisting of a single division of 
the stem. It may possibly attain a more luxuriant growth; but 
I have examined a considerable number of specimens, and have 
always found it to be either simple or furnished with one or two 
short branches. 
The polypite, when fully extended, is a singularly beautiful 
object, imitating to some extent the form of a tall and graceful 
candelabrum. Only the base of the body is within the calycle. 
