298 
Auicud^. ANNELIDA. T ubicola. 
organs are wanting. The feet form a projecting series 
of lobules along each side, and are all of essentially the 
same structure ; in general they consist of two branches 
armed with bristles. These are mostly compound, and 
in each bundle there is a spine of the usual form. In 
the greater number of instances the feet are provided 
with two filiform, awl-shaped cirrhi, which in some are 
transformed into compressed laminae or leaflets. The 
branchiae ai'e simple in structure, but their existence is 
sometimes doubtful. They are usually in the form 
of lobules or tonguelets placed on the feet, and dis- 
tinguished from the true lobes of the feet by being 
destitute of bristles or any antennae. The Nereis 
(fig. 203) will illustrate this family.* 
Family V.— ARICIIDiE. 
This family contains several genera, and a consider- 
able number of species. Their body is in general 
elongated and linear, like the Nereides; but it is not 
truncate anteriorly as in these worms, and is smaller 
nearest the anterior extremit}^ It is usually cylindrical 
in form, and consists of numerous short segments. The 
head is very small, conical or rounded, in most of the 
species possessing no antennse nor eyes. The proboscis 
is small, somewhat membranous, and is destitute of 
jaws. The feet are divided into two branches which 
are not very projecting, but armed with simple seta- 
ceous bristles. The branchiae are either wanting alto- 
Fig. 
gether or are very simple in their structure, exhibiting 
the form of a setaceous or lanceolate filament reflected 
on the back, or elongated and spreading, and frequently 
clothed with large vibratile cilia. The species of this 
family are miners in wet sand or mud, and are found 
inhabiting slightly' cemented sand-formed tubes. 
Families VI. and VII.— PERIPATIDiE and 
CH^TOPTERID.®. 
The families Peripatidce and Chcelopteridce consist 
each of only one genus, and only one species has as 
yet been described belonging to each of these genera. 
In both these families the feet are prominent and fur- 
nished only with bristles properly so called, and there 
is a total absence of distinct cirrhi. 
Family IX.— ARENICOLIDJE. 
This, the last family of the order Errantia, appears 
to establish the passage of the animals belonging to it 
into those of the order Tubicola; M. Savignj', indeed, 
places them along with the Serpulce. The Arenicoloe 
are of a cylindrical form, and the body consists of only 
a small number of rings, but these are divided by a 
multitude of transverse pleats. The head is merely 
rudimentary, and the mouth is terminal and furnished 
204 . 
Arenicola piscatorum, or Lug-worm. 
with a small retractile proboscis, but is destitute of jaws. 
There are neither cirrhi, antennm, nor eyes. The feet 
are uniform in structure and composed of two branches, 
the dorsal branch being armed with simple bristles, 
and the ventral with a series of imbedded, hooked bris- 
tles. On a certain number of segments in the middle 
portion of the body we find the branchiae in form of 
* There are several genera belonging to this family, as 
Nereis, Si/llis, riiyUodoce Nephtliys, Glycera, &o., &c., but there 
is one which has a remarkable form, and which has been de- 
scribed as a new genus by the late Dr. Johnston of Berwick, 
and hitherto undescribed, wliich we should like here particu- 
larly to mention. He has named it Gattiola, in compliment to 
his friend Mrs. Gatty, authoress of the well-known “ Parables 
from Nature.” It has a body consisting of about fifteen seg- 
ments, deeply indented at the sutures and narrowed in front. 
The small, flattened head has three long, filiform, nnjointed 
antennas, four eyes, and two pairs of tentacular cirrhi, similar 
to the antennas. The feet are composed of only one branch, 
and the bristles are compound and falcate. On.y one species 
has as yet been described ; it is a native of England, and has 
been called by Dr. Johnston Gattiola spectabilis. 
well developed arbuscles. The figure we here give 
(^Arenicola piscatorinri) will give a good idea of the 
family'. — See fig. 204. 
Order II.— TUBICOLA or SEDENTARIA 
{=.CapitihranehiatcL), 
The Annelides of this order are so called from the 
great majority of tliem living in tubes, which, from the 
organization of their bodies, they' are incapable of leav- 
ing. They are hence also named sedentary animals, 
as the tubes they inhabit are frequently permanently 
fixed. The body of the animals is worm-shaped, cylin- 
drical, generally swollen or thickened on the anterior 
portion, while the posterior is smaller, of less diameter, 
and sometimes distinctly defined as a bristleless appen- 
dage. It is composed of numerous short segments; 
the head is ill defined, not distinguishable from the 
anterior segment which contains the mouth ; and there 
