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AETICULATA. 
ORDER 1. ERRANTIA. 
THE NEREIS. 
This term means wandering, and is applied to numerous species, of wliicli the Lob-Worm or 
Lug-Worm, Arenicola piscatorum, is a common example. This animal, much used by fishermen 
for bait, is nearly a foot long, and is found on sandy parts of the coast, where it bores into the 
sand left wet by the retiring tide ; its head is large and rounded, quite destitute of eyes or ten- 
tacula, and furnished with a short, unarmed proboscis. The feet are very small, and confined to 
the anterior part of the body, while the branchial tufts, which are of considerable size, are placed 
on each side of the middle segments. 
The family of Aphroditidce, some species of which are known as Sea-Mice, includes certain 
marine animals of great beauty. In these worms the body is generally broad or ovate, the head 
small, and furnished with very short tentacula ; the feet are large, with immense tufts of bristles and 
spines, often of the most remarkable forms, and exhibiting the most brilliant metallic colors. 
Each of these hairs is retractile within a horny sheath, which serves to protect the soft parts of 
the animal from injury by its own 
weapons. The Common Sea-Moubb, 
Aphrodita aculeata, is oval-shaped, six 
or eight inches long, two or three wide. 
Cuvier says that the covering of this 
animal does not yield in brilliancy to 
the plumage of the humming-birds, or 
even the most shining gems. 
The family of Nereides includes some 
elongated and distinctly annulated 
worms, which possess a well-developed head, famished with tentacles and eyes, and a mouth 
with a proboscis, which is sometimes furnished with two or four teeth. The cirri or tentacles 
attached to the feet are often of considerable length, and sometimes even annulated. The ani- 
mals frequently present an appearance strongly re- 
sembling that of the more elongated Myriapoda. 
In the next family, the ^unicidce, the branchial 
tufts are of considerable size, and the mouth is 
armed with from seven to nine toothed jaws. This 
group includes some species of large size ; the 
Eunice gigantea, which inhabits the West Indian 
seas, grows to the length of four or five feet ; and 
others, found in the Southern Ocean, are said to at- 
tain double that length. 
Zoologists also place in this order a curious ter- 
restrial annelide, found in the West Indies, and 
called Feripahcs. In its general appearance it ex- 
hibits a most striking resemblance to some of the 
Millepedes. The Leodice antennata has the organs 
of locomotion attached to each segment : they are 
usually in the form of movable spines, and are used 
as oars. 
ORDER 2. TUBICOLA. 
THE SERPULA CONTORTOPLICATA. 
Tlie worms belonging to this order are all marine, 
and are distinguished by their invariable habit of 
forming a tube or case, within which the soft parts of the animal can be entirely retracted. 
This tube is usually attached to stones or other submarine bodies. It is often composed of 
various foreign materials, such as sand, small stones, and the debris of shells, lined internally with 
