362 
POLYZOA. 
adhering to sticks, stones, or leaves, or even lying freely in the water ; others being flat and 
ramified, like broad-leaved sea-weeds ; others spreading film-like over leaves, stones, shells, or 
similar objects ; while a few are able to crawl at liberty, the entire organism being animated 
by some wonderful instinct, which urges all the myriad individuals of which it is composed to 
employ their force in the same direction. 
The number of these creatures is so vast, that it is impossible to give more than a brief 
description of them ; but in the following pages it will be found that a careful selection has 
been made of the typical forms, and that sufficient details of their structure will be given to 
enable the reader to form a general idea of the subject, and in most cases to refer any speci- 
mens which he may find to their genera or families. Those who desire further information on 
the subject will find it in Busk’s elaborate catalogue of the Marine Polyzoa, and the large 
work by Allman on the Fresh-water Polyzoa. 
Putting aside the classification of the polyzoa until the termination of the work, we will 
proceed at once to the description of the many species of this class. 
The first family of the polyzoa is known by the manner in which the cells are arranged 
around an imaginary axis, and connected with each other by flexible stalks. The general 
shape of the whole group, or “polyzoary,” as it is termed by some authors, is very shrub-like, 
standing boldly erect, and giving out branches by two and two, after the fashion called by 
botanists “dichotomous.” 
An example of one of these beings, the Little Chain, or Breast-plate, is plentifully 
found in the sea, and is properly classified among the zoophytes. The Catenicella Jiastcita is 
somewhat remarkable for the shape of the cells, the form of their mouths, the method in 
which they give out their branches, and the peculiar organs called technically “avicularia” 
and “ vibracula the former being processes that in many species bear an almost absurdly 
close resemblance to the heads of birds ; and the latter, curious hair-like projections, which 
move regularly backward and forward as if impelled by machinery. These remarkable organs 
will be presently described more fully. 
The members of the present genus are found most commonly in the Australian seas, sel- 
dom in the southern hemisphere, while in the northern hemisphere they are almost entirely 
unknown. Many specimens have been taken from Bass’s Straits, at a depth of forty-five 
fathoms. As a general rule, however, the polyzoa prefer the shallower waters, and are most 
commonly found a little below low- water mark. 
Another species belonging to the same genus is remarkable for the long pointed spines 
that project from the margin, like a pair of cow’s horns. In allusion to this peculiarity it is 
called Catenicella cornuta. 
Another curious polyzoon, termed Calpidium ornatum , is also found in Bass’s Straits, at 
the same depth as the preceding species. It shows a singular method of construction. 
Each cell is extremely wide in proportion to its depth, and instead of possessing but one 
mouth, it is pierced with three apertures shaped something like keyholes. It is conjectured 
that each cell is inhabited by three separate individuals, a supposition which is strengthened 
by the great comparative dimensions of the cell and the thickness of its walls. Still, no sign 
of internal partitions have been discovered, although some remains, apparently of the inhab- 
itants, have been seen at the bottom of the cell. In some cases there are only two apertures to 
each shell. 
An example of the typical genus of this family is the Salicornaria farciminoides. The 
strange specific name of this creature is given to it on account of its external resemblance to 
the Farciminaria, another genus of polyzoa which will be presently described. In this genus 
the cells assume a kind of honeycombed aspect, being almost hexagonal in their shape and 
pressed closely together. 
In this place it may be as well to mention that in all the species belonging to the first sub- 
division of the polyzoa the mouth is not quite at the extremity of the cell, is of a somewhat 
crescentic form, and furnished with a movable lip or door, which closes the aperture when the 
animal retreats. In many cases this lip is membranous. All the marine polyzoa are termed 
Inf undibulata, or Funnel-shaped animals, on account of their form ; their fresh-water relations 
